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Adoptable Storage on LG Stylo2
I recently bought a 64GB SD card. Soon discovered adoptable storage is disabled on Stylo2, so I can't change app storage from Internal storage to SD card.
I followed instructions on another forum of how to enable adoptable storage on my phone using ADB commands.
It worked.
But now, my "Storage & USB" Settings shows both Internal Storage and SD card, but File Manager only shows Internal Storage.
And instead of having 16GB internal and 64GB external, File Manger is only showing 10GB TOTAL!!!
It seems like it was partitioned incorrectly.
Is there any way I can fix this?
I'm including a pic of some screenshots of the problem, and the code I used. I really hope you can help!
Correction: I've been exhausted, so I thought maybe I missed something. I looked back over the code from the other forum and over the code I entered. I missed line 3, so I  went back and entered the code, but the problem remains. The code is as follows:
sm set-force-adoptable true
sm partition disk:179,64 private
sm set-force-adoptable false
sm list-volumes all
Would be nice to partition 8GB or so to adopted storage, the ramaining 56GB of the 64GB SD card to "portable"/external storage.
I will probably see e-mail replies before I see them here..
blakburner at gmail dot com

I removed your email address based on Can I give out my e-mail here? and Would that be okay to put up an email address for more help?

For the disk were did you get the 179,64 numbers from? Reasoning devices can be different and there are some commands missing from your list. One being the command that gives you the partition disk numbers. The command adb shell sm list-disks which will give your devices partition disk numbers.  Yes, you can delegate a percentage of the sdcard for internal then the rest with something else. You use mixed and desired percentage of space you want seperate instead of private at the end of the am disk:179,64 private. Example: sm partition disk:179:160 mixed 65

I should add the flow of the commands to set adoptable storage:
adb shell
sm list-disks
(This returns disk id numbers {xxx,xxx or xxx_xxx} which you input into the partition command)
sm list-volumes all
sm set-force-adoptable true
sm partition disk:xxx,xxx or xxx_xxx
sm set-force-adoptable false
sm list-volumes all
important reboot device
Once rebooted go to Settings --> Storage & USB and tap your SD card. Tap the three dots in the upper-right hand corner and then choose Migrate data.
Are these the command and order/sequence  you followed??

179,64 was what was in his code that i copied. Sorry though, I've been outta tech stuff for a while, but im not totally unfamiliar from my younger days, so I'm having to adapt to adb commands and terminology. That being said, what is the difference between 'mixed' and 'private'. Have my thoughts, but be better if i just let you clarify.     The other forum didnt include the cmd sm list-disks, nor did it mention Migrate data.

Be nice if I could put a few returns to separate the lines in my comments, but every time I press enter, it hits the blue Add Comment button instead of doing a line return. Guess I can't separate anything correctly lol. Guess I need to brush up on my code to manually enter. [P] or  perhaps lol. I even copied and pasted from notepad app, which had line returns..still none here smh

And just for curiousity, if my goal is to enable adoptable storage, which is what the code you've given does, and partitions the SD card, then why the "sm set-force-adoptable false" code? Seems like that would do the opposite.

Update: mixed vs private..i found the answer to that. Question though. Let's say I have 16GB internal storage and 64GB on SD card. Im wanting to partition 24GB of the SD for internal/adopted and leave the remaining 40gb as public/portable for music, etc. By selecting Migrate Data to SD card, I'm setting primary/emulated storage to the partition of the SD instead of my actual Internal Storage. Instead, can I simply partition the SD as mixed so that 24gb is private(adopted/internal) and not choose Migrate Data, so that my actual Internal Storage remains primary? Which would leave me with 40gb...

...Which would leave me with 40gb total internal storage (16gb actual internal + 24gb adopted) and 40gb public/external storage.

So, I entered the code you suggested, but I did not choose Migrate Data yet. Waiting for your response.
Results:
SETTINGS>STORAGE & USB>Device Storage:
-Internal Storage (16GB), SD Card (~40GB), SD Card (Not Inserted)

Portable Storage:
-SD Card (22GB)
FILE MANAGER:
Internal Storage (10GB)!!!???
SD Card (22GB)
I have screen shots that make a little more sense.
Pretty much though, according to Storage & USB, I have a combined total of ~52GB Internal (was only wanting 40), and 22GB external (was also wanting 40).
But File Mgr only shows 10GB Internal! & 22GB external.

Update:
I after re-partitioning the SD card and having the incorrect percentages, I re-partitioned again.
Now I have under Device Storage: 16gb Internal, 22.23gb SD (adopted), and 2 other SD cards ("not inserted"). And under Portable Storage I have 36.86gb SD card (which would be the external partition ofcourse. A lot closer to the numbers I was wanting. Any idea what's up with the 2 extra "not inserted" SD cards?
Is it from the 2 previous partitions? I would assume those partitions were mounted, and now they're not there, but the mount point is? If so, should I unmount them?


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location via WiFi, cell tower not working anymore
I have a Nokia 8 Sirocco with Android 9 (kernel version 4.4.153-perf+ #1). Since a few weeks ago I noticed that the phone seems to be unable to get its non-GPS based location - e.g. via WiFi locations or cell tower triangulation.
The symptoms are:

Google Location history is less accurate.
My shared location only updates for the other persons whenever an app uses GPs (and there is a GPS signal).
I keep seeing an "Updating your shared location" notification.
Apps that rely on location services take longer to boot up or be responsive.
Apps that rely on location services do not work at all without an available GPS signal.
Location based Smart unlock is not working.
Location based reminders are not working.

I have checked the following settings under Security & Location » Privacy » Location:

Under Google Location Accuracy the Improve Location Accuracy is On.
Under App-level permissions all relevant apps have permission to access the device's location.
Under Scanning both Wi-Fi scanning and Bluetooth scanning are On.

Is there anything more I could do to get this working properly again?

Wild shot- try disabling location accuracy, reboot, enable and check

@beeshyams while this seems to have worked initially for a while - the behaviour is now back again unfortunately. This makes me conclude that either a) there is a bug within Android 9 or b) there is a bug that occurs with Android 9 only on the Nokia 8 Sirocco or c) something is wrong with the phone itself.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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How to change the font of only one application?
There's an app called JuiceSSH and it's running perfectly but whenever I change my phone's font it via themes app, JuiceSSH acts weirdly inside the terminal: weird spaces and letters show. My question is how to change the font of this app only to something default, I've tried using APK editor and it always says failed to compile, and I've no idea what should I do. Can anyone please help?
(Running Android 8.1, EMUI 8.2)

What app are you using to change the font? Is it a manufacturer specific app (e.g. Samsung)? What phone?

Themes, a system app that comes with the phone, Phone is Huawei Y9 2019.

Why don't you just contact the author of JuiceSSH and ask for a in-app font selection mechanism overriding the default system theme?

I've tried this and no hope, they're not answering and seems like this program is no longer maintained, it's just thrown there on playstore with no support

Apparently it was caused by using a non monospaced font, when I used a monospaced font on system it actually got fixed but still, I'd like to know how to set a default font on an APK.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Can I safely charge a SGS9 device with a 5.2V MacBook Pro 2018 USB-C charger?
Can I use 87W USB-C Power Adapter for MacBook Pro to safely charge a Samsung Galaxy S9 device? I'm curious as on the charger it says the output is 5.2V, while the phone seems to require 5V.
The specs of the Mac's charger can be seen on this image:

According to Wikipedia the USB specification is:

USB supplies power at 5 V ± 5% to power USB downstream devices. (source)

5% of 5V are 0.25V
Therefore any USB device have to be able to work correctly as long as the "received" power via USB is within the range of 4.75V to 5.25V.
The Apple USB power supply with 5.2 Volt is within this range.

I was about to answer on similar lines but realized that the charger follows USB PD not regular USB. So while your answer is correct that it can charge safely the reasons are different as explained in my answer

Yes, you safely can charge

The Mac Charger follows USB Power Delivery (USB PD) as you can see in the picture you pasted.

USB PD is a different standard from USB Type C, in that it supports broader charging specs which was initially based on profiles and later evolved to Power Rules. These are well explained in What are USB PD Power Rules?. Quoting relevant extract :

The new rules also introduce a “superset” guarantee. Larger wattage power sources must support all voltage levels below their maximum up to 3A. As the spec says, “Bigger is always better in user’s eyes – don’t want a degradation in performance. Higher power Sources do everything smaller ones do”
As a result, the consumer only needs to know that their device ships with a x watt power supply, and know that any power supply that is rated at > x watts will be at least as good as the one that shipped with the device.

(Emphasis supplied)

Also see the questions at the bottom of the 87W charger you linked. It talks of an iPhone charging (Can the 87W USB-C power adapter be used with the NEW iPhone Xs Max? and will it damage the Xs Max?) which supports this (while mechanics of iPhone charging are different, the standard is the same)

Related from SE.Ask Different which confirms what I said Is the Macbook 12 inch's USB-C charger interchangeable with other USB-C chargers or devices? - this is in the context of USB Type C charging and the same logic holds and more strongly for USB PD.

I wonder why there's no USB PD after 5.2V - 2.4A on the charger.

Probably space constraints or missed out. But rest assured that it has to be USB PD. It can't be PD for some voltages and not for some other voltage - what purpose would that serve and how would it charge the iPhone (last bullet point)? Besides, that would mean it is NOT following both standards ;)

See last portion edit


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How Android's permissions mapping with UIDs/GIDs works?
Reading the book: Android Security Internals I'm reading at Chapter 2 - Permission Management paragraph that permissions are assigned to application at install time by the package manager with a mapping like Apk's UID <-> Permissions.
Later in the book (Permission Assignment - Permissions and Process Attributes paragraph) I read that

If additional permissions have been assigned to the application, they are mapped to GIDs and assigned as supplementary GIDs to the process.

And, since android.permission.INTERNET permission is associated with inet GID:

any process for an app that has been granted the
  INTERNET permission is associated with the supplementary GID correspond-
  ing to the inet group

But I was asking me if this is always necessary.
Imagining a case where you install APK X declaring android.permission.INTERNET permission in AndroidManifest.xml, since mapping of permissions with UIDs is done at install time, PackageManager should be able to map the permission directly with the APK's UID instead of adding inet GID to your APK package. So I'm wondering why it has to be that:

any process for an app that has been granted the INTERNET permission is associated with the supplementary GID correspond- ing to the inet group

Anyone can clarify me this?

That is simply the way it works. Checking if a user is member of a specific group is much simpler than on every request having to check if a user is authorized to this and that.

Android's permission management can be divided majorly in two parts: Linux kernel and Android framework.
DISCRETIONARY ACCESS CONTROL:
Discretionary Access Control (DAC) based on users, groups and access mode predates back to early days of UNIX. Every file (including directories) and process has a user owner (UID) and a group owner (GID). So a process is allowed to Read Write and eXecute a resource depending on its access mode bits (RWX) for User, Group and Others (UGO). These permissions attributes are saved along with files on filesystem.
UID/GID 0 is special for Linux kernel; it's the super user (administrator) that is never denied from doing anything. All other users in range 1-65534 are non-privileged IDs which an OS can use in whatever way it wants to control access.
Android reserves UIDs in range 1000-9999 for system use unlike Linux distros where 1000 is usually the first UID assigned to human users. Android is designed for single human user but every Java app, whether preinstalled (as system or user app) or installed by user, is treated as a user. UID range 10000-19999 is reserved for these apps. At first boot (for preinstalled apps) or when installing a new app, a unique UID/GID is assigned to the app which is static unless the app is uninstalled. This app vs. UID mapping can be seen in file /data/system/packages.list or using command id (1) if the app provides a shell or can execute native binaries.
All of these UID's have hard-coded names on Android which are predefined, unlike Linux distros, where there are almost standardized naming conventions for users and groups which can be added / removed in /etc/passwd and /etc/group. Android shares only root user name with Linux. However these names are only for the ease of human users, for kernel only numbers (UID/GID) mean.
Access Control Lists (ACLs) can be used to extend DAC for more granular privileges but those are rarely used on Linux and (AFAIK) not used on Android.
LINUX CAPABILITIES:
Root user's authorities are further divided into subgroups called capabilities. Instead of using UID 0 whenever an elevated task is to be performed, a non-privileged UID can be granted only the required capability. File capabilities which are attached to files using Extended Attributes (XATTR), can also be used to elevate process capabilities whenever required. Android makes use of File Capabilities as well as Ambient Capabilities. See this thread for more details.
MANDATORY ACCESS CONTROL:
Mandatory Access Control (MAC) was introduced later to supplement DAC for better security. Android uses SELinux as part of its security implementations. SELinux also makes use of Extended Attributes to label files with a context while every process is also run with a SELinux context. Then a policy is defined which includes thousands of rules allowing one context access the other, denied otherwise by default. See this answer for more details on SELinux and an example how Android makes use of DAC, capabilities and MAC.
By making use of Linux kernel's DAC, MAC and capabilities, Android launches every app in a sandboxed virtual machine forked from zygote process, with its unique ID and with all capabilities dropped, so that forced to access only it's own files in /data/data/<app_pkg_name> or in external storage. See this answer for more details.
MANIFEST PERMISSIONS:
To have a further fine-grained control of system resources, in addition to Linux's access control mechanisms at kernel level, Android enforces it's own Manifest Permissions to installed apps within its core framework. These permissions are of three types: Normal, Dangerous and Signature.
All normal permission are granted to a requesting app without human interaction. For instance a user can't restrict an app from accessing internet if the app is requesting android.permission.INTERNET. Some of such permissions are controlled by using third party tools.
Dangerous permissions - such as READ_CONTACTS - aren't granted to an app without user's approval. Some of Signature permissions treated as Special permissions - such as REQUEST_INSTALL_PACKAGES - can also be controlled from Settings app > Apps & notifications > Advanced > Special app access menu on newer Android versions.
Additionally some of the permissions for which user doesn't have independent control such as GET_ACCOUNTS, or the operations which don't have corresponding permissions at all such as RUN_IN_BACKGROUND, can be controlled from a hidden permissions manager of Android: AppOps. But this is meant only for OS use and not for end users.
PERMISSION CHECKING AND ENFORCING:
Permission preferences are stored by Android Package Manager in different files such as /data/system/packages.list, /data/system/packages.xml, /data/system/users/0/runtime-permissions.xml at app install time or at runtime. These permission checks are then enforced on multiple events such as when accessing intents, starting an activity, sending/receiving broadcast, accessing a content provider, starting/binding to a service etc.
Though the whole permission checking and enforcing process happens under zygote in which ActivityManager and PackageManager - which are part of system_server - play major role, the core framework doesn't handle every permission check on its own. It again takes help from kernel to make permission checks more robust and efficient.
For instance READ/WRITE_EXTERNAL_STORAGE permissions are enforced through UIDs/GIDs by bind-mounting different views of Storage in a mount namespace for every app. See this answer for further details.
PERMISSION <--> GID MAPPING:
Another special case where Android relies on Linux kernel for permission check is android.permission.INTERNET. As stated earlier, only UID/GID 0 is special for standard Linux kernel. However Android applied a special patch PARANOID_NETWORKING to Linux kernel which maps certain capabilities to certain group IDs in range 3000-3999 making them special. One of those is INET (3003) group which allows its members to access internet (create PACKET sockets) which isn't possible without capability NET_RAW otherwise. All permission <-> GID mappings can be found in file /system/etc/permissions/platform.xml.
Coming to your question:

since mapping of permissions with UIDs is done at install time, PackageManager should be able to map the permission directly with the APK's UID instead of adding inet GID to your APK package

So the answer is, PackageManager doesn't handle android.permission.INTERNET on its own. It just adds the app to INET group and saves the configuration. Let's take example of Termux:
~# grep termux /data/system/packages.list
com.termux 10142 0 /data/user/0/com.termux default:targetSdkVersion=28 3003

Next time the app is launched with 3003 in its supplementary groups so that kernel doesn't restrict the app from accessing internet when enforcing DAC:
~# ps -p $(pgrep com.termux) -o cmd,uid,gid,supgrp
CMD                           UID   GID SUPGRP
com.termux                  10142 10142 3003,9997,20142,50142

SOURCES:

Dissecting Android Permissions
Android Application Launch explained
Configuring DAC on Android


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Android smart phone wont turn ON

When I try to turn On my LG L7, it shows

Device temperature too high or low. Please move to another place to charge.

And it wont turn ON.
It started after I tried to measure voltage between the electrodes where the battery goes using a multimeter.
I think I messed up it by shorting positive and negative.
What can I do? Please help

May be you killed the temperature sensor of the battery. Remove the battery and wait for an hour. Then try again. If it does not work you may have to replace the battery.

It doesnt work. Is there anything I can do. I think I must have damaged the charging module of the main board

What does not work? Replacing the battery?

yeah. Replacing the battery


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Cannot open PDF file using Google Drive app
My device is running on Android Oreo, and I have study notes as a PDF file on Google Drive (link to the file for testing), but I can't open it on Google Drive app.
My file is not opening and it's saying "No connection" even though I've got an awesome connection. I don't know why it's not syncing my file.

I've even cleared cache, refreshed my Google Drive, and also rebooted my phone.
How to fix this issue so that I can open my PDF file from Google Drive app?

It looks like a bug with Google Drive. I had the same problem in opening the link
Workaround
I pasted the link in Chrome and it opened! You should report the bug, also
in Playstore

(Click to enlarge)
To download the file, open Chrome in desktop mode and click the  option (print).

What I do, because I have the same issue, I use Open With option works like a charm. I use the Google PDF Viewer

Oh, lol, but at that time I've got no other option s other than this


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Use 4G while being connected to a WiFi direct printer
Is it possible to use 4G for internet while being connected to a wireless printer with WiFi direct?
If not, are there any alternatives to use both, the printer as well as the internet, simultaneously without requiring another WiFi access point?
(The printer in question is the Epson L3150 Wireless Printer)

Does your device has the option "Cellular data always active" (Settings -> Developer Options)? Note that the developer options have to be enabled first.

If Epson or the device manufacturer has a printer plugin in Google Play store for wifi then you don't have to use wifi direct.

This is an ongoing issue that has been described as an optional implementation of the wifi direct. Or rather a lack of implemented options. My self a team testing an app for a developer, found that some phones have an option or feature for load balancing over wifi and data as a feature. Those that have this balancing, print and access internet without issue. Those without have no data over cellular while connected to wifi.

I was looking to the similar solution with my 360 camera and I found it. Even though my problem seems to be more complicated than yours. I needed some app to get data from internet while my phone wifi was being used for wireless connection with the camera. The app just always wanted to use wifi to get data and ignored all settings and even restrictions through mobiwal to use mobile connection only.
Below is where I asked about it and described a solution before I got any answers
Need wifi to be connected to a camera(no internet) and one app using 4G for internet
In your case, why don't you want to try to do it as simple as that:
1)create a hotspot on your phone where your 4G connection
2) connect your printer to the hotspot?
I did almost the same but in my case I used a second phone just as a hotspot. The reason I had to do it that way is I cannot connect to anything from the camera directly so I had to go through Wireless LAN client mode as a feature of the camera. In your case your printer should have some kind of screen that can help to connect to your hotspot.


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VPN not working in kitkat 4.4.4
I am using Lenovo A6000 running stock rooted Kitkat 4.4.4. And since about 6 months the vpn has stopped working properly. Everytime I connect to a VPN via mobile data, it connects and then gets disconnected after about 10 seconds and the 3G/4G icon vanishes too momentarily.As a result the VPN disconnects, rendering it useless.
I tried everything, different VPN apps, factory reset, wiped system, data, cache, dalvik cache, internal storage. Nothing fixed the problem.
This problem does not exist in 5.0+ android but i really don't want to update because anything other than stock Kitkat is buggy and drains battery heavily.
Anyone know how to fix this?


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How to root Mi TV 4A?
I tried all rooting technique but nothing is working
Problem no 1: I can't use USB debugging options (don't have USB to USB cable) but I can able to use adb over network after boot.
Tried all kinds of apps: Kingroot, Towelroot, Kingo root.
Nothing is working ☹
I have a useless recovery mode (because of USB to USB cable, I cannot connect).

Tv model: Mi TV 4A
Android: 6.0.1
No Gapps

Have suitable TWRP & need to install TV Gapps.
Note: It's not a TV box.


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Seemingly dead Sony Z5 Compact gets detected as QHSUSB Bulk
My 2 year old Z5c (E5823, non rooted, official Sony Nougat update) died while updating some app, and doesn’t show any signs of life since then. Connecting the charger doesn’t turn on LED indicator, but it does consume about 0.90A. I have tried all different reset procedures, and only the first time I tried the 2-minute reset did it vibrate once or twice. Since then it doesn’t ever vibrate either.
If I don’t press the power button before connecting to Linux, then it gets detected as QHSUSB__BULK (Manufacturer: Qualcomm CDMA Technologies MSM) only. However, if I reconnect it , then it gives a USB error related to "USB power limit exceeded” :
device descriptor read/64, error -110
I need to then either disconnect the batter or press the off button next to Sim. My first priority is to recover its data (the phone was encrypted however). And if possible, fix it. I couldn't find its schematics to confirm if it's a hardware issue or bootloader (hard bricked), and would greatly appreciate any tips or advice to further diagnose or fix it.


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Is possible to read the memory from my phone (S6) in recovery mode?
I have a problem with my Samsung S6, it restart continuously in a loop, I can see the home screen and interact with it but only for 5 or 10 seconds before it boot again.
I think the only solution is to reset the phone, but I want to backup my data first.
I can enter to recovery mode, and also download mode, is possible to make some backup from there?
I have tried connecting my phone in recovery mode and "adb devices" returns empty, I can see the device connected only in sideload mode (Apply Update from ADB)
My phone is not root

You cannot get access to your data through stock recovery. Stock recoveries are designed to format the data and cache, and flash OTA updates. Offering shell access through recovery is a risk to user's privacy so it is naturally avoided.
That said, I had noticed in the past some low-end MTK chipset devices' stock recovery offering (could be in encryption unsupported devices only) an option to backup user data. But even that backup is stored inside phone's storage which presumes that the user can boot into Android normally and get hold of it.
In short, you need to look elsewhere to get hold of your data. Stock recovery is no good here.

I've decided to format everything, I lost my data but at least not my phone


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Creating copy of phone (apps, settings etc.)
I have two rooted Huawei P9 Plus phones running Android 7. Now I would like to copy the apps, the settings of the apps, the system settings etc. from one phone to the other phone so that both phones are exactly the same.
How can this be easily done? I have root, so I could also use an app requiring root.

Depends on "the other device". Are they identical devices (i.e. same model, etc)? Then check our [tag:nandroid] questions. If not: TitaniumBackup can do most.

@Izzy Yes, they are completely identical devices

I can no longer answer here – but then the best way is using a [tag:nandroid] backup created on one and restored on the other. Unless you want to do that on a daily basis, then that might take a bit too long :)

It can be done using many ways,

if you use the same Google account on both devices then just a simple cloud restore from the initial setup screen would setup everything just the same. (when I was switching roms frequently which are all based upon lineage, or same feature sets, I noticed even personal settings appeared to be restored along with all apps, messages and other data) So I think It'd be the easiest.
Mentioning root You could also use apps like titanium backup etc (btw I faced lot of after restore stuff like setting up permissions for each app and its just for the apps) also do note that new apps for doing the same are also available.
Assuming you are rooted on both of your devices with a working twrp recovery(as with most cases) and every config of both phones being the same then you can do a nandroid backup (backup from twrp menu) to your sd card transfer the backup folder to your other phone and then restore it there.
ps.
(tl;dr I don't recommend this to you by any means but It can work taking your case.)
I haven't tried it on two phones and would have a high chance of breaking your phone if things doesn't match well (nandroid backups can break even on cases where the new roms doesn't match older ones)


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Why does flashing my Tab3, 7.0, 8GB, WiFi (sm-t210) fail with Odin?
I tried several versions of Odin and also several ROM's, yet successfully flashing still seem to fail.
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/005> Added!!
<ID:0/005> Odin engine v(ID:3.1301)..
<ID:0/005> File analysis..
<ID:0/005> Total Binary size: 1397 M
<ID:0/005> SetupConnection..
<ID:0/005> Initialzation..
<ID:0/005> Get PIT for mapping..
<ID:0/005> Firmware update start..
<ID:0/005> NAND Write Start!!
<ID:0/005> SingleDownload.
<ID:0/005> PBL.bin
<ID:0/005> FAIL!
<ID:0/005>
<ID:0/005> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1

Please observe that with the newest version of Odin in the log above 'Get PIT for mapping' and 'PBL.bin' failed.
<ID:0/005> Added!!
<ID:0/005> Removed!!
<ID:0/005> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> T210XXBNI1_T210PHNBNI1_T210XXBNI1_HOME.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/005> Odin v.3 engine (ID:5)..
<ID:0/005> File analysis..
<ID:0/005> SetupConnection..
<ID:0/005> Initialzation..
<ID:0/005> Get PIT for mapping..
<ID:0/005> Firmware update start..
<ID:0/005> SingleDownload.
<ID:0/005> PBL.bin
<ID:0/005> NAND Write Start!!
<ID:0/005> FAIL!
<ID:0/005>
<ID:0/005> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

Please observe with an older version of Odin that in the log above 'Get PIT for mapping' and 'NAND write' failed.
The stock ROM I seem to need for this device 'SM-T210, Tab3, 7.0, 8GB WiFi, has these specs: KOT49H, T210XXBOB1, PHN, build date Feb 3 2015, Android version 4.4.2
Kernel version: 3.4.5-4081557
I'm not sure if it's KitKat or Jelly Bean as both seem to have similar versions of Android.
So what's going wrong here?

I've been trying several versions of Odin, from the newest to the older versions 1.85, 1.87. In the mean time I've been trying yet another version of Odin 3.07 and that seem to finish successfully, yet on the Tab3 I don't see any progressbar, nothing. So when the device reboot after Odin finishes ... nothing seem to be changed. I'd try other USB ports too, but that didn't do the trick. All being left for now is another cable. Until today I've been using a Nokia branded charge/data cable, which seem to work fine for browsing the Tab3. But this week will show if that's the cause of failures.

Are there specific requirements to that micro B USB cable in use with either Odin of Samsung?

Many times I tried to repair that device, but when the volume up/down buttons start to fail, it is game over. So I had to quit.

As Odin in Windows doesn't seem to work for my device, I tried another application such as Heimdall-Frontend.
This application differs from Odin in that it uses the extracted files from a stock ROM where as Odin uses the stock ROM to upload to an connected device.
Anyways, I found that from Heimdall all files are successfully downloaded to the Samsung Tab3 device.
Yet there was a slight difference between the download of 'system.img' file and all the other 9 files out of the stock ROM.
After the download from Heimdall completed, it was released and right after that the Tab3 device goes into reboot.
While after the download of all other 9 files, it took a few seconds before the Tab3 goes into reboot.
So my guess here is that right after being released, the Tab3 goes immediately into reboot and deletes that way the successful downloaded 'system.img' file.
That would also explain as to why there's no change after the successful flashing with Heimdall.


text:
Is it possible to see which process is calling the zygote socket?
I want to see a verbose from the zygote socket (located in /dev/socket/zygote ) I know i can list all of the services from adb but I wanna see who is calling zygote to fork an specific process. Do you guys know how?
My question does not have an answer, but i made a little code in python that allows me to see the PID of any process listening to the zygote socket

Sniffing UNIX domain sockets isn't straightforward. You need to use strace or something similar on process instead.


text:
Prevent screen from turning on/off automatically due to interaction with the internal magnetic on Nexus 6
I have a rooted Nexus 6 running on Lineage OS 15.1 (Android 8.1). The internal magnet that is supposed to turn the screen on and off when a magnetic case flap is shut is making it really difficult to use my magnetic car mount.
Is there any way to turn off this feature?

I see an old Xposed module https://www.google.com/amp/s/forum.xda-developers.com/xposed/modules/disable-magnetic-sensor-phone-sleep-wake-t3296354/amp/


text:
A non-existing app keeps crashing
I've removed an app long ago, but when I unlock the phone a message appears which says: "the app" has stopped
I had changed its location from internal to external before I remove it.
Also I have another app which keep stopping, I changed it to external too.
I cannot rechange the apps which I changed their location after I've updated  android system
These two apps are not English
J7 prime 2017
Android 8.1.0

Try installing the app again and then uninstall

Still apears , and about the other problems?

One problem at a time is a better approach. Try uninstall following this answer https://android.stackexchange.com/a/204485/131553. Also [edit] to add device details and Android version

Didnt work. This app is not in my application list at all!

I would try finding the folder where the app was installed and deleting the files there after it is uninstalled.  It sounds like it is not removing the actual program completely.

Thank you but I've tried this way and I didnt folind the folder

Sometimes, a corrupted cache can make the system behave unexpectedly.
So, try clearing the cache partition from the recovery mode on android. It solves most issues.

Didnt work... you know, sometimes it appeares and then after a restart it disappears! Now it is not appearing after unlocking but maybe after one restart or max power saving mode, it is begining its bothering

What was the app and what type of app was it?

A non-english application (kind a book), also I have problem with these kind application.

Did you install it from play store ?

Nope. Of course

Go to Developer settings->Running services. Check whether that app is running in the background or not. If that app is found, it means that it was not completely removed from storage.

I found it, now how I should uninstall it completelly?

Click on that app in running services list, then click on the 'Force stop' button. Then restart your device.

Didnt work  I want u check this out https://1drv.ms/v/s!Ap0XhcNArOiBgUpe3QVPr3NSN5DO

Sorry, I can't see it because I am working on Jio phone. And I do not have any other device. Can you say what is it?

Yeah, I turned it off in the 'check background' menu, but it becomes on again when I come back to it. Even I try restart

Are you sure that the app is not listed in the applications list?

I am pretty sure, even in developer settings>inactivate apps you can not find the app! The only place I found it is the "check background" list! Even there is no folder of the app. I am really tired

You can root your device and manually remove the app's installed files. OR, if you want a hassle free way, you can perform a FACTORY RESET.

Now we are talking. It was just because of secure folder. It contains many deleted apps( but in its own way)


text:
Google play store app installation history
What would cause the Google history to show certain apps installed, but then uninstalled, all at the same exact time or within one minute of each other?

Maybe the apps were updated during those times.

So are you saying that when apps are updated, they automatically uninstall and reinstall? Is that certain?

It's my theory yes. Even on a PC most apps (programs) when they are updated, the old version must be removed in order to install the new. To be 100% sure, update in the near future an app and check if their activities will be reflected as uninstalled and installed as shown on the images you posted

Did you test? What were the results?


text:
Can't send emails from huawei tablet using outlook address
We have got my son a huawei tablet, and he has an @outlook.com email address. He can receive emails on the tablet, but can't seem to send any-they say they are sending but never arrive, nor do they appear in sent folder or drafts? What am I doing wrong? Thanks

You can check the SMTP server settings of your mail program. The SMTP server is the one used for sending E-Mails.
The recommended settings for the SMTP server for @outlook.com is:

Server: smtp-mail.outlook.com
SMTP port: 587
SMTP encryption method: STARTTLS

If it still does not work your network may be blocking port 587. But that would be a problem of the network and not a Android problem.

Ok thanks-I’ll try that. How would I find out if my network was the problem?

@user289433 Try different networks like mobile data, home Wifi, Wifi somewhere else. If it works using one network and not using another the networks has obviously an influence.

Have tried all those, various wifi networks and on mobile data. Still nothing. Any other ideas? Thanks


text:
Use gps position of another phone
We have a paraplegical friend that loves to play pokemon go (one of the few activities that his condition allow him).
Even so, the care that he needs does not allow us to bring him outside.
We would like to allow his phone GPS to lock onto another droid GPS, and so he can "walk" with us around the city, and stay at home where can can be taken care.
I´ve found how to do that with Bluetooth, but we need to do that over internet...
Any clues?


text:
How do I understand the storage usage of an application? How do I solve my phone becoming slow?

When I installed the FB application, the size was 49MB. As recommended, I then move it to the SD Card. I expected that the memory internal usage would not be so congested. The app was working fine initially. But later, the app and my phone was working very slowly, and many times stopped working. Then I checked, and I found the memory usage's status is very different between installation and the current. There are 237MB memory occupied (after I cleared cache the memory), and only 55.88MB stored on SD Card.
Then my question is, where is the rest of the app is stored? In internal memory? How do I solve my phone from being very slow?

There is a lite version of this application designed for low memory device. You should try it

Yes, that FB Lite I also installed. But there is limitation with the number of characters I can write in the status. It limited me to write my though.

49 MB is the size of the installer, the install itself will be much larger. And moving an app to external storage does not move every component of an app, you will never get a 100% data move.
Not sure who advised you to move facebook to external storage, but it is best practice to leave apps on the default install location (interal memory for most apps). External storage is not directly attached to the phone motherboard, and MicroSDHC SDXC card speeds are lower than internal soldered-on memory. So unless you are running critically low on space for internal memory, leave facebook in (or move it back to) internal memory.
Also, don't have both facebook and facebook lite installed. It's a resource burden and may even cause conflicts. For the sake of speed, go with facebook lite if you can. But uninstall one of them.
About cache clearing. Although "cache cleaners" and similar tools look good, a cache clear is at best ephemeral and at worst annoying as all the apps that needed cache in the first place need to repopulate. The exception that proves the rule is facebook...clearing cache once in a while frees up a ton of memory and noticably improves performance. Facebook cache is the one cache item I do delete manually from time to time.
If an uninstall of one of your two facebook apps, and a move back to internal memory, and a facebook cache clear don't help, you'll need to investigate other possibilities.

Quote: Not sure who advised you to move facebook to external storage, but it is best practice to leave apps on the default install location, I did it just because I worried that the internal memory will not be enough. I normally did it as more apps installed, the more slow the phone. I will try to reinstall it and leave in internal memory to see if it is help.

In addition to facebook, I suggest moving as many other apps as possible back into internal memory. I would leave at least 200-300MB free for proper OS function but other than that, unused memory is wasted memory.External memory is best used for user files such as documents, pictures, videos, music etc.


text:
Is it possible to use multiple accounts from one email address in K9 application?
In the company I work for We would like to use one general email address, but different accounts. Is it possible to do that?

AFAIK, it's not possible (Related How to setup K9 Mail properly for free email services offering multiple aliases for same email box?)
K9 mail isn't really active in development and I would rather suggest you switch to a modern Email Client which does this and much more. I am talking of FairEmail. Don't be discouraged by "unreleased"  status. It's very much functional and actively developed. See this XDA thread.
Specific to your query see FAQ 9
I am not associated with the app but would happily recommend this being a better alternative to K9 mail - it's leagues ahead of K9


text:
Google Chrome - remove old tabs
When I click on a link, Chrome opens and the link will be displayed in a new tab.
However all my previous tabs are still there. By clicking multiple links again and again a new tab is opened. Over the time Chrome is stacking dozens and dozens of tabs.
How can I stop this? I don't want to manually close each and every tab.
Even closing Chrome (swipe away Chrome in recents overview) does not delete the old tabs.
I have tried reinstalling Chrome and it still shows this behavior.

Indeed Chrome on tablet is really missing a "Close all tabs" button.


text:
External Hard Drive to Smartphone without additional power supply
I) Goal
Use external hard drive without power supply - no hub either - to backup smartphone directly.
II) Configuration

Huawei Mate 20 Pro, this - I own this.
USB C male to USB A (3.0) Adapter (i.e. OTG adapter), this - I own this.
any of the following external hard drives:

WD ELEMENTS PORTABLE 4 TB WDBU6Y0040BBK-WESN - I think about buying this.
LaCie Rugged Mini 4 TB LAC9000633 - I own this, brand new & ExFAT formatted.

III) Problem
I don't know the power output of my smartphone or the power requirements of those hard drives exactly and am therefore not sure if my goal is achievable. When I connect my LaCie 4TB to my phone - via said USB-C-A-Adapter or directly via a USB-C-cable - the drive is not recognised and doesn't seem to spin.
IV) Known information / How I am trying to solve my problem
According to this and this my goal is achievable, according to this (Android Enthusiasts) maybe not.
I searched the web, but didn't find any official/trustworthy information from the manufacturers, from sellers or from users about the power in or output of either of those devices. The following information regarding the HDDs I found seems somewhat ambiguous:

WD = 1 watt (WD on Amazon, somewhat trustworthy, but only info about 3TB version, here).
LaCie = max. 2.9 watt (quite trustworthy actually, here).

My smartphone is able to supply an Apple Keyboard (wired) and an Apple Mighty Mouse (wired) at the same time over said OTG Adapter and a USB hub (hub power supply not plugged in!)... But I don't know the power consumption of those peripherals.
V) Main Questions

A) Is my goal really achievable? How?
B) Is my assumption right, that my LaCie HDD won't spin because of power supply issues?
C) Will the mentioned WD HDD do the job? If no, other suggestions, please.
D) How do I have to format my drives to be read by Android? (I've read ExFAT should work...)

VI) Additional, optional Questions

E) What are the actual power requirements (in watt) of those drives? What is the actual power output of my Smartphone over OTG? Maybe someone with experience (and/or who has these drives) knows those numbers? Don't bother looking into the spec sheets of those drive, there is no information about the power requirements in there.

VII) Disclaimer
I know, these aren't questions directly regarding Android. But,

first, there is no Stack Exchange Site about Smartphones,
second, I was sent here by the people of the Electrical Engineering Stack Exchange Site after posting this very question there (and deleting it now),
third, my smartphone is an android device,
forth, this might be a Android-ExFAT format problem (?),
and fifth, the Android community is really competent when it comes to tech questions,

so this is the right place for this, I think... Please don't hate on me for posting my questions here - I shall kindly migrate to another Stack Exchange forum if you know a more suitable one.
Many thanks.
VII) Update

Confirmed by Huawei support: The Mate 20 pro has 1 Ampere / 5 Volt output.
Confirmed by LaCie support: Said LaCie Drive - and as it seems every thing hooked up via USB 3.0?! - needs 0.5 Ampere (no voltage info) to function properly. - So why doesen't this work? Too low voltage?

One suggestion is to connect via adb over WiFi and see if the logcat provides any info about USB connection status.

Can't answer your question fully, but just to confirm, I have used Western Digital Elements SE Portable Hard Drive (WDBPCK5000ABK) - 500 GB formatted with NTFS on Xiaomi Redmi Note 4 (mido). But the power consumption was high enough, might be causing discharging of battery at harmful rate.

A) Is my goal really achievable? How?

Unsure, see the answer to the second question of item E.

B) Is my assumption right, that my LaCie HDD won't spin because of power supply issues?

Yes. The HDD isn't spinning up because the power supply isn't sufficient.
Another reason would be the HDD being broken otherwise, but this is unlikely the case given your very detailed description of your problem.

C) Will the mentioned WD HDD do the job? If no, other suggestions, please.

For the same reason as B, this is unlikely. 2.5" HDDs nowadays have a fairly similar power consumption, regardless of brand. Older HDDs and HDDs with higher capacity tend to draw more power, but not making a huge difference.

D) How do I have to format my drives to be read by Android? (I've read ExFAT should work...)

Nothing. You're done it correctly - exFAT is the right filesystem for them.

E) What are the actual power requirements (in watt) of those drives?

As given in whatever you've read. Those claimed power requirements are usually correct.

What is the actual power output of my Smartphone over OTG? Maybe someone with experience (and/or who has these drives) knows those numbers?

So, this is the most tricky part...
I haven't used any Huawei phones, but from my past experiences phones don't output much power (usually less than 2W) to OTG devices. It's likely that your phone is doing the same - not supplying as much power as needed by the HDD.
From previous news (in my local language Chinese - sorry), Mate 20 / Mate 20 Pro is capable of running as a power bank, or "reverse charging". I'm guessing that the claimed 5V/1A output is only achievable in reverse charging, not OTG.
The conclusion is not quite delighting - you have to get some kind of external power supply before you can use your HDDs with OTG.

Many, many thanks for your in depth answer! I guess I have to use a memory stick then... :) About D): I formatted a Stick yesterday to FAT32 via computer (Mac) and it wasn't "read" by the phone; instead it asked me whether I wanted to format it via said phone, which I did. It was formatted to ExFAT and was "readable" by my Mac. But - as I wrote in the original post - when I format something via Mac to ExFAT it doesn't seem to be "readable" by the phone... Strange...?!

EDIT: Your answer to my last question makes my following comment redundant...: [About E): Well, according to my info - see "update" above: Phone output 1A/5V and 0.5A/na.V needed input by the LaCie eHDD - the connection should work properly, if the unknown needed input voltage of said LaCie isn't insanely high... Also strange...]

Ok, I'll try reformatting the HDD via phone to ExFAT now over a Hub. But it seems that I really have to bring along said hub or buy a stick - which isn't a problem, but I hoped this would work as demonstrated by a user (https://bit.ly/2F0ISWO - do you know what eHDD this is??) and as the background picture of the backup app suggests (https://bit.ly/2UsHT6R - kind of mean...), because there is so much more storage space on a HDD. Also, a hub defeats the purpose of a one cable eHDD... Thank you for clarifying this for me, though! :D

I use a Sundisk Dual flash drive (https://www.sandisk.com/home/mobile-device-storage/ultra-dual-drive-usb-type-c) for my backups now, which works fine with Huawei's preinstalled backup app - the only thing is, that the drive can wiggle somewhat and then disconnects... So in the end, the problem above is not solved but I've a workaround; I'll marke the answer above as solution and might test another external hard drive I have which is powered by a separate USB cable (separate from the data USB cable) a try one day. Thanks to all contributers!

This is a wild guess but may be worth a try.  On my Mate 20 Pro, if I go to 'Developer Options' in the Settings, there is setting for 'Select USB Configuration'. The default option is 1) Charging (which I presume means power on the way in to phone) but there are also options for 2) MTP (Media Transfer Protocol), 3) PTP (Picture Transfer Protocol), 4) RNDIS (USB Ethernet), 5) Audio Source and 6) MIDI.
Perhaps if you try one of these other options with the OTG cable, it may do something?
Like I said, a wild guess based on poking around in Settings since I've had the phone.

Welcome to Android Enthusiasts! None of those options will unfortunately help with powering up an external HDD.

I conform Reddy Lutonadio's comment. But thank you for your idea! :D


text:
Automatically insert recipient name in WhatsApp's broadcast message
I have a broadcast list of about 115 and would like to send a broadcast message on WhatsApp and personalise the message to each person.
The message would read:

Hi <Name>, thanks for spending time with us. Have a good day further.

I know there are codes for fonts and text effects but if anyone knows of a code that would allow me to do this I will be very grateful.

AFAIK, WhatsApp only supports simple text formatting, so for more complex automation like this, perhaps 3rd-party apps are needed (not yet researched though).

you can use the custom WhatsApp broadcast tool for web.
It automates sending of custom message uploaded in a csv using web.whatsapp.com
Link to the program
https://whats-app-dialer.com/#broadcasthtml


text:
Is there a way to set the maximum total cache size?
The cache on my device (Samsung Galaxy S5, unrooted!) grows very quickly. Is there a way to just set the maximum allowed system-wide cache size?
My device always restarts (and takes a while restarting too!) whenever I manually clear the whole cache.
Edit: I have an external 128GB SD card too but S5 only treats it as a simple mount, not as an automatic extension of regular device storage (16GB capacity!)

I use Cache Cleaner, an open source software... You need to enable clean on open, and close after clean ... Then just tap to clean cache.... https://f-droid.org/en/packages/com.frozendevs.cache.cleaner/  might be an alternative..

Sounds like you need more storage. You shouldn't need to clean the cache except for maybe a rom update or clean install.


text:
For basic users - Any reason to install mobile security App?
For users that play it straight, never going to doubted sites, never enabling APK from non-play sources... (e.g typical seniors)
Any reason to install a mobile security app?
Because

Such users always surf magazines and news sites. Maybe YouTube.
As for Trojans: Official APKs are inspected by Google. Non official APKs are disabled by Settings. Seniors hardly install what they don't know. It's mostly WhatsApp, maybe some 2D game from Play, and that's all.
Worms & vulnerabilities: If your phone is old and stops getting security updates, nothing can help you. Antivirus apps are apps. Hence, they can't protect you because they can't monitor and filter traffic.

Under those assumptions, for senior users, Antivirus for mobile is nearly useless. What am I missing?
Thanks

Related: How do anti-virus apps for Android work?

tl:dr Yes, you need such apps and more a wholistic approach

Breaking down the possible threats (simplistically) :
1.Viruses: They don't exist on Android. See Is an antivirus really needed for Android?.

malware : Yes a very real threat that is usually piggy backed on apps or users being lured to click spammy links and download payload.

Since you mentioned simple games, to see the possible threat, see Flappy bird malware
You are also making an assumption that reading news sites is a safe. Not true. ANDROID WARNING: Terrifying malware can spy on almost EVERYTHING you do on your phone says

The second one was the preferred vector: we found several news websites that have been hacked by the attackers to redirect visitors to a downloading site that serves malicious APKs

(Emphasis supplied)
How to counter this threat is quite beyond the scope here, but suffice it to say you need protection both in terms of user education and apps.
Personally, I find Addons Detector to be reliable for app related threat. But this scans apps after they have been installed so a better approach would be to scan before installing by using Yalp Store which lists all the Play store apps and importantly gives out a report from Exodus scanner (which you also can use directly via its website). Another way of doing pre-install check is submitting the app apk to Virus Total (Thanks to Izzy's suggestion)
Several malware detection apps are available and it is upto your discretion to choose.

privacy:  Apps invading your privacy is another big threat. Apart from choosing open source apps which reduce this possibility, real protection often requires rooting your device, which is not what an average user does.

Tangentially, as one grows old, convenience takes precedence over security and apps can easily invade their privacy (permissions).

Your second bullet point is highly debatable. You are assuming that Google Play scanning is robust and therefore offers adequate security.

This is simply not true. A Google search for play store apps removed shows at least three instances in last six months when apps were removed from Play Store. One may say that this is evidence of Google tightening security but OTOH your target group of senior citizens may have already been affected! Quoting from one report picked at random to emphasize this

The report also adds that some of the apps dated least a year back and had been downloaded million of times.

Alternative is to install open source apps from f-droid. I do agree that equivalents are not always available but such security apps discussed earlier  have a role in supplementing defense.
Choosing open source apps and user education reduces  risk partially at least along with selection of right malware apps.
What started as a comment, turned into a long answer (and incomplete). That said,  premises of Google Play Protect screening being robust , assuming news websites to be safe or downloading simple games as harmless are not necessarily true as proved often, time and again.

Additional information

Trackers packed into apps are a threat and while ways have been suggested in the answer, for additional information see What’s it all about those modules apps contain?
App permissions is another troublesome aspect and is beyond casual users, much less target users of senior citizens. For a primer on permissions and to see how how crazy, it actually is, see The Android authorization model: a perfidious construct

Sourced from Izzy's blog (thanks)

Thank you for revising this. Addons Detector is a good thing you suggested. I'll check it out. +1 though. :)

Addon Detector is a good suggestion – but doesn't that only work for apps you have already installed? That's already too late then in some cases. So additional suggestion: Check Exodus before (if the app comes for free), or Appbrain (which also lists libraries for paid apps, but is less complete). If Exodus lists 20 trackers (well honestly, strike the 0), crap the app. If it has a few, check their descriptions to decide. Avoids a bunch of potentially dangerous apps. If the APK is available, uploading/checking with VirusTotal and/or ApkScan is another potential measure one can take.

Thanks. Yeah, basic users like seniors and, frankly, most of the people, are hard to educate to internet caution. I suppose that an AV is the least of the worst. Even worse, I have seen updates to preinstalled apps that became malware (e.g Galaxy S6 IR manager). I wish I could have had a more wholistic solution, but ... when it comes to technophobes, this will have to do :( Thanks again

"I have seen updates to preinstalled apps that became malware" – never seen that on F-Droid. So really, safest way is to deactivate all GApps you don't need – and only use apps from F-Droid, as @beeshyams already suggested. Minimizes risks considerably (though it cannot help against "drive-by downloads"). And speaking of ads: my Android app lists give you a good idea of how many trackers etc. come with one app (but not with the next one that covers the same functionality).

@beeshyams thanks for integrating! I just added the link for Exodus.

If you wish :) Let me know what you want me to cleanup then. Apart from the last 3 (this one included), I'd say the comments are still useful.


text:
How dumb is it to try to remount /proc as w?
I'm trying to run a little python code that check some files in my phone's /proc/pid
the thing is the program won't run properly because /proc is read only. Because I know proc has a special filesystem I want to know if there is a way to remount it as writeable without screwing up the system

Will adb shell cat /proc/whatever... adb shell first, might give you shell access to the file.

/proc is a pseudo-filesystem supplied by the Linux kernel, so as to provide an interface to applications to learn about system runtime information (running processes, mounts, memory, etc.). Therefore there's no way to "mount" it as R/W since that's meaningless.
Some entry points (NOT files), however, are writable by themselves, for example most entries under /proc/sys. Do note that by writing to these entries you're not writing any files, but actually changing system parameters.
If your program is trying to write to another non-writable entry in /proc, it's probably malformed and should be tweaked. Again, /proc is not a real filesystem and everything inside are interfaces from the Linux kernel.
Read more (related or similar):

deleting a 'file' under /proc or /dev
Which files are writable under /proc and why?
(programming-related)

Documentations (usually very long and complete and unsuitable for casual read):

proc(5)


text:
OEM Unlocking Greyed out after Android 8.1 Update. (Lenovo Tab4 10)
I purchased a Lenovo Tab 4 10, I enabled OEM Unlocking, Unlocked the Bootloader to root my tablet, and when I booted back into the Android OS it had an update, so I updated it, rebooted, re-enabled Developer Options because it had turned it off after the Android update, now OEM Unlocking is greyed out, I've cleared cache, factory reset it, tried tricking it with dates, waited 10 days to see if there was a lock period, and it's still greyed out, tablet Bootloader now says "LOCKED" and I can not Re-enable OEM Unlocking to unlock my Bootloader again.
I'm Stuck and Any Help or Ideas would be Appreciated, I can find almost nothing on this tablet. so any help is greatly appreciated!
The Specs of my Lenovo Tab4 10 ( this is NOT the Plus or the LTE Version.) are below. :)
I Thank Everyone For Their Time :)
Model: Lenovo TB-X304F
Kernel Version: 3.18.71
Build Number: TB-X304F_S001014_181113_row
Hardware Version: Lenovopad TB-X304F
Software Version: TB-X304F_RF01_181113
RAM: 2GB
Storage: 16GB
CPU: Qualcomm Snapdragon 425

I had that problem too. NAT was the root cause.


text:
Samsung note9 adb over USB keeps disconnecting
I have my Samsung Note9 (updated, on latest Android 9) connected via USB on Ubuntu Linux, latest platform-tools_r28.0.1. When I run adb shell, it works perfectly. The problem is, the device disconnects after the while (about 30 seconds).
I have the "stay awake" option enabled, but even if the screen remains on, adb keeps disconnecting. I discovered when I prevent the phone from sleeping by touching it, adb remains connected.
Am I do something wrong?
Thanks

Try revoking USB authentication, reboot both devices, connect and authorize. May help - guessing

This scenario seems work: after the first disconnection, switch USB mode to charging only and turn-off, turn-on USB debugging without disconnecting USB.

Well, if that is consistent you can make that an answer

hmm, no, it worked just for a little bit longer...

Sounds to me like a defect USB port (loose connection)


text:
How to know whether TrustyOS is running in Android mobile or not
I'm referring TEE(Trusted Execution Environment) for Android Here. Can anybody help me to check whether any device is runnning Android along with Trusty OS?

This question on Stack overflow may help: https://stackoverflow.com/questions/48515838/client-application-and-trusted-application-in-trusted-execution-environment-tee

There is this app on Github - tee-checker, it's latest version is 3 years old (!) but it detects TEE on Qualcomm devices.
On my MiA1 it shows

(Click to enlarge)


text:
Delayed notifications on Huawei Mate 10 pro with Android Pie, EMUI 9.0
What I experience these last months is that notifications from various apps of mine  do not appear in time.
Either they appear very late or not at all (until I open the specific app).
My system is Huawei Mate 10 pro with Android Pie, EMUI 9.0.
What could be the reason for that?

Likely reason is battery saving feature of Huawei which is a stronger version of doze-mode, in that apps are frozen if inactive after a duration. I had seen this on my earlier Huawei device. See my answer here. What is protected apps in Huawei phones?.
It looks like it is not called "protected apps" anymore and this Reddit explains the required settings to disable this for apps. There is also a feature of Power Genius involved and a workaround to bypass that. Options mentioned in Reddit

See if you can find a way to turn off battery savings in this Location or similar Settings- apps & notifications - apps- settings cog- special access - ignore battery optimisation >allow/disallow

Or

Settings -> Apps -> Apps -> three dots on upper right corner -> special access -> battery optimization -> change dropdown menu to "all apps" -> change apps you want to keep in background to "don't allow, may drain battery more quickly

Edit: OP confirmed that the second option was the right one for their device. Thanks
Disable battery saving feature for those apps and hopefully that should fix delayed notifications.


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Disable Bixby on Galaxy S9 without root?
I have read this question and realised that it is outdated.
With the most recent android update for my Galaxy S9, I have no way to disable the Bixby button out of the box. Previously I had to sign in to Bixby, Then go to setting and disable the button there. Afterwards I could remove the samsung account and had no issues at all.
How can I get rid of Bixby/disable the bixby button without rooting the device?

Software update: G960FXXU2CSB9/G960FOXM2CSB3/G960FXXU2CSB3
Android version: 9
Security Patch: 2019-02-01
Bixby Home Version 3.0.02.6
Bixby Voice Version 2.1.04.18

I bought a flex case for my S9 and used a razor to saw off the case's raised button. No Bixby here unless I want it. Also, I don't have or want a Samsung account. Don't know why anyone would want it.

You can disable the Bixby button by using
Bixbi Button Remapper - bxActions. This allows you to remap the button to another action.
As for disabling Bixby altogether, I am unsure of how to do it.
Another mention was enabling developer options, then scrolling to the bottom of that menu to Background Check, then disabling the options for Bixby in there. I did try this, but it did not disable the Bixby Button, nor am I sure it actually did anything with Voice.
You can still remove Bixby Home by holding on the main screen then navigating over and disabling Home.

bxActions seems to work, though bixby still pops up very briefly on double click. I also tried the developer options and had no success as well

I have just jumped straight from Android 8 on an S7 to Android 12 on an S10+, so I don't know if this works on any other version than 12:

Go to: Settings > Apps > Bixby Voice
Select "Disable"

After this, the button appears to do nothing.

Similarly, disabling the "Google" app appears to prevent that popping up after a long-press on the home "button".


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Why does Google Maps ask me to rate places I haven't been to?
I am asked to rate places Google Maps thinks I have visited. I have not been there and I click on "I have not been there". But the next time, I still get asked to rate those places I have chosen as "I have not been there" before.
How can I stop Maps from asking me to rate places I haven't been to?

If you were near a business for enough time to count, Maps might guess the you visited the business.
GPS location is imperfect, esp. with multiple businesses in the same building or GPS signal reflections among tall buildings.
WiFi location might also apply, and sometimes WiFi base stations get moved to new locations.

If someone else is logged in to your Googe account on another device and visits the place in question it might push the notification to your device.

Nobody is logged in to my account but thank you


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Microphone Permssion in Pie not listing all apps
I have a Pixel phone. Recently I checked App permissions →Microphone permissions, and it shows 5 of 24 apps allowed.
But when I open the microphone permissions, it lists only 4 apps. Is this normal behaviour ?

Thanks for editing your question. I am deleting my answer because I can't help with the missing 3 dots. Maybe some Pixel owners can help

@androidbeginner Did you confirm with a 3rd party app like Addons Detector or aSpotCat?


text:
Has android inbuilt support for zip files?
Please try to understand this question carefully before marking this as duplicate.
Do the Android OS has inbuilt support for .zip and .rar files ? I am not asking about any third-party software, because I know that there is a difference between OS support and software support. I am asking this because I have found bootanimation.zip and shutdownanimation.zip files inside /system/media/ folder.

Android does not contain any program-code for reading or writing RAR files.
For ZIP files Android has support for reading/extracting and creating new ZIP files (Android APK app files are ZIP files therefore reading them is required for running Android).
However the functions for handling ZIP files are only available on development level, therefore any Android app can read or create ZIP files.
The only app I know that can handle ZIP files is the default app

Files (com.android.documentsui) which is available by default on a large number of devices (some vendors replace this app therefore it is not available on each an every device). Note that this app is not available in the Google PlayStore.
There are no command-line programs that can handle ZIP files (to be used e.g. via adb)


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Flashlight problem on Android
I have recently faced a problem on Android regarding the flashlight.
When the flashlight is turned 'on', the flashlight icon in the status bar gets highlighted.
When I am turning 'on' the flashlight, it is staying on for sometime and it automatically gets switched off suddenly after some time, but the icon in the status bar still stays highlighted, which indicates that the flashlight is turned on. Same thing happens for the front flashlight.
Can anybody say what can be the reason for this automatic and  random turning off of the  flashlight ?
Additional information : There is no fixed time interval for the automatic switch off, it is occuring randomly.

I have an opposite issue, my icon will remove itself from the menu all together and i can not turn off the flashlight.... I think android has issues with flash light apps at the best of times... The flash is just that, a flash... Using the LED as a torch is possible, however it's not really designed for it..  Usually overheating causes an issue etc... Most androids in my experience have issues with flash light torch apps.. Even the default Video recorder has limit's on certain device's... A custom application or widget might be an alternative, some apps can handle the flash intensity etc...

Yes, heating of the flashlight may be a reason, but since I don't use my device so much, it does not get heated. Sometimes, even when the device is cold, the flashlight turns off just a few seconds after it has been turned on.

As you have said, I have tried many apps, including my self-made apps, but it doesn't seems to solve the issue. Even when I turn on flashlight from the camera app, I face the same issue.

Sounds like residue, have you used it near water or maybe splashed water on it... It sounds like some kind of short circuit

If you have root access, Add these build props and try tweaking them..... ro.media.capture.flash=led
ro.media.capture.flashMinV=3300000
ro.media.capture.torchIntensity=65
ro.media.capture.flashIntensity=70

I think you are right. I haven't ever splashed water over the phone, but the phone had once got dropped while charging. But I can't root my phone, because my parents have still not afforded a PC.

Let me see, whether system update, wiping cache partition or factory reset can solve this or not. If it doesn't, there must be some hardware issues.

Some device's can be rooted using Applications directly on the device, i tried several and the most successful ( But also most invasive ) is KingRoot ... At one point, Android 5.1.1 days.. it could root 93% of all androids vulnerable to the Universal signature .. Problem, bug? idk what you'd call it... However, it sends your IMEI number and other unnecessary information to the server while gaining root... Other apps are KingoRoot, Framaroot, Towelroot, Etc.... Have a look around and test a few.  Android 6.0 + may require a custom recovery to gain access by flashing Super SU or Magisk...

My stock software shuts down my headphones at full volume by stopping whatever is playing... I used Engineer Mode to lower the headphones output and everything works fine... Sometimes it's just bad development or quick development with a few oversights...

Thanks for your rooting suggestions, but all those programs had failed to root my phone.

I have got a technique to deal with this issue.
I have booted my phone into recovery mode and wiped android's cache partition from there. Since then, the flashlight issue seems to have flown away.
I mean, now the flashlight is not automatically turning itself off.
@Zillinium, I think you should also try this method to deal with your issue. If that doesn't work, a system update or factory reset might do the trick, if there is no hardware problem.

It's very strange that the cache caused this issue... Anyway I'll give it a try.

For me, it's not anything strange, because once after restarting my phone, I had noticed that the speaker was not working at all !  From then, I came to the conclusion that software bugs and corrupted cache can affect hardware performance.


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Redirect calls not from my contacts to another phone number?
Is there any way to redirect/forward calls that are not from my contacts to another number?
(No, I'm not looking to block them or redirect them to voicemail.)

Related https://android.stackexchange.com/questions/123942/forwarding-calls-from-certain-callers?rq=1

@Reddy: Is the first sentence in the answer a typo? It says "I doubt that this will not be possible for an app to do".

I wrote "Related". Whether things have changed since that answer is something else.

@ReddyLutonadio: Yeah I imagine they haven't changed much, but that's not what I meant -- I meant the answer says "I doubt that this will not be possible" (i.e. it is probably possible) but then proceeds to argue why "I doubt that this will be possible" (i.e. it is probably impossible).

@Mehrdad thanks for spotting the typo in my answer. Fixed it. I believe your current question is a dupe of that and am voting to close on this account. You can always edit your question to say why it is not. Thanks


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Phone reboots randomly
Bought 'Redmi Note 4' phone a year ago. Random reboot issue started happening after 6 months. Did root & had flashed old/new/unofficial ROMS on my phone afterwards, uninstalled CPU hogging apps still it didn’t fix. Tried every single post from MIUI forum but no luck. Recorded ADB logcat to trace system logs on my PC.
Any help would be appreciated. Thank you.
Current phone details Screenshot =>

Here, 26 seconds log filtered with only ‘Error’ tag just before it hanged & rebooted itself on its own =>
https://justpaste.it/3m8rd

You rooted after the issues presented or before?

@SiXandSeven8ths Ofc afterwards to verify whether this issue also persist in older/custom firmware.

Have flashed new persist.img from a proper official ROM. Has been 3 days & it still boots randomly :(


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Not getting the lock icon in the recent apps list
I came to know that there is a lock icon on every app in the recent apps list in the overview in android that allows us to pin some apps to the list.
I am using Android 7.0 , but I am not getting any such icon there. See this screenshot :

Is there any hidden setting in Android by which this functionality can be enabled ?

https://www.techrepublic.com/article/how-to-make-use-of-the-android-nougat-recent-apps-lock/

I think you haven't understood my question properly. My question is how to enable that feature, because the lock icon is not there on any of the apps (see the above screenshot).

Did you mean screen pinning? Open Settings-> Security & location->Screen pinning.  Enable it. Also, enable 'ask for pattern before unpinning'. These settings are from android 9.0. And, for 7.0 you can search for screen pinning from search option top-right of settings page.

https://stackoverflow.com/questions/46613909/lock-an-app-on-the-recent-apps-screen-prevent-user-from-closing-it-when-certai

@RahulGopi no, this is not about screen pinning. Now I don't remember if I had this feature on stock Nexus 5 (perhaps not because it's too old), but per-app lock is there on the "recent apps" when I started using Lineage OS.

@AndrewT. I am running also 9.0 stock android, also don't remember the same used in Oreo and nougat. But. for custom UI devices like xiaomi, have still such options.

No, no, I know very well about the screen pinning feature. I am talking about the tiny lock icon beside the cross mark on the top bar of the recent apps list, by which we can lock individual apps to the recent apps list. The link which you provided me at first. My question is 'how to enable that feature' ? That is by default, not enabled in my phone.


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My keyboard got removed when updating to Android 8 Oreo
Yesterday I updated my Samsung S7 (SM-G930F) to Android Oreo version 8.0.0.
After the update I do not have any keyboard, just the Google's Voice Typing is showing up when I would like to type something.
Before I had the original Samsung swedish keyboard that came with the phone.
The numpad is working when I'm looking for typing number e.g. when dialing.
But whenever I need to type something else than just numbers, I do not have a keyboard.
Under settings -> Keyboard: There is only Googles Voice Typing and I have tried everything without any luck.
I do not want to reset the phone to default.
Anyone got any hints what to try?
Remember that it is very hard to try anything without a keyboard...
(All is in swedish so the translation might not be the correct one)

which keyboard you've used previously? please check settings-> apps-> keyboard app, check whether it is disabled or not.

I can not find anything in -> apps that has to do with a keyboard.

I don't think that it is swedish keyboard, may be samsung keyboard or google's gboard.

You can download this Samsung Keyboard. It supports Swedish

have you found any keyboard app in app launcher or settings->applications->applications manger. Otherwise you can try Izzy's answer on this link(N.B: backup is recommended). https://android.stackexchange.com/questions/44964/no-keyboard-after-factory-reset-cant-install-keyboard-on-phone-with-bluetooth

Thanks Rahul Gopi and beeshyams -
Since I could only "type by voice" I didn't manage to find the Samsung Keyboard, but I manage to install gboard so now I at least have a keyboard to work with, eventhough it is not as good as the normal Samsung keyboard I'm used to...

happy to hear that the issue is solved. Normally, the keyboard app on device will be a system app(installed factory). You cannot uninstall system app or it don't get removed after OTA update / factory reset. you can just disable/enable it.

Well, my Samsung keyboard app was factory installed by Samsung and somehow it still got removed with the system update. Very strange and annoying.

Now that you have Gboard , you can go ahead and install the Samsung Keyboard and if that helps you, please go ahead and self answer :). It may help someone with similar issue

I've tried, but I actually have a hard time finding the Samsung Keyboard in Google Play Store.

I did as Rahul Gopi and beeshyams commented.
But since I could only "type by voice" I didn't manage to find the Samsung Keyboard, but I manage to install Google Gboard so now I at least have a keyboard to work with.
So now it would be easier to try to install my normal Samsung keyboard...


text:
Need urgent help in fixing soft-bricked Moto G5s
I was trying to root my Moto G5s. I did a mistake while flashing twrp, I flashed cedric instead of montana. As a result, whenever I reboot, I am getting error:
    Start Up Failed:
Your device didn't start up successfully. Use the Software Repair Assistant on computer to repair your device

And the FastBoot terminal kind of thing that appears below shows
Error: Failed to load kernel
Boot up failed

I downloaded a boot.img of stock rom but don't know how to flash it. I tried using command
fastboot boot boot.img

This boots up to stock rom but whenever I restart, I get same error. Also when I boot with that image, my wifi doesn't work. Can someone please help me. It is urgent as I don't have another mobile.

Why don't you boot directly into the correct TWRP using fastboot? Run fastboot boot YOUR_CORRECT_TWRP.img. From there, flash the correct recovery, and if needed, correct boot image too. Also, note that we are  volunteers here. So, please don't expect  urgent help.

@Firelord can you please tell me any site to get latest Moto G5s stock rom. its name is montana


text:
Phone/Text/Contact History?
Does Android keep a log of numbers contacted similar to the Phone Call Log/History but for texts?
My mother accidentally deleted a bunch of texts. The actually messages themselves are unimportant, but now she has completely lost the contact number and I am wondering if their is a way of pulling up the number of the last text(s) sent.

No. It doesn't. They are not backed up like apps,settings and call history. Only on Pixel phones SMSes are backed up.
There is a possibility though - If she had called that person and if backup was enabled on the phone and if she remembers the date and time when she spoke (lot of IFs) then you could take a backup of all important stuff on the phone do a factory reset, restore from Google backup and reconstruct from call history, to get the contact number . It's a slim chance  with so many IFs.
You need to weigh the efforts of backing up data and restoring the phone subject to her remembering when she called and of course backup being enabled on device


text:
How to set up a socks5 with Android cli?
I found articles how to set up a http-proxy. But can't find any info, how to set up a socks5 proxy. My goal is to route all traffic from apps, etc throught this proxy. Is this possible? How then programs like Drony work?

Android does have HTTP(S) proxy support built-in that can be set through Settings UI and/or command line, but it isn't global, so regarded by proxy-aware apps only. However there is no built-in support for SOCKS. So if an app - unlike web browsers - cannot be configured to use SOCKS proxy, there is no way to set SOCKS5 proxy from adb shell or terminal emulator without using a third party tool / app. See details in How to set Wi-Fi HTTPS proxy, not HTTP, via adb shell?
HOW PROXY WORKS?
See this answer for HTTP(S) proxy.
SOCKS proxy - a complete handshake protocol - creates a tunnel at lower level than application proxies (http/s) in OSI model, so UDP traffic can also be transported. However the connection isn't secure like https and the security depends on initial authentication during handshake. socks can be used by individual clients or can be set system-wide i.e. to transparently forward all traffic. A common application of latter case is encrypted SOCKS tunnels like SSH dynamic forwarding, Tor, shadowsocks, stunnel, ssf, sshuttle, obfsproxy and so on. A VPN is also an encrypted tunnel but it operates even below SOCKS, therefore able to carry all IP traffic and forward every port.
HOW TO SOCKSIFY:
Apps force all traffic towards a SOCKS proxy in two parts:

Establish a connection between client device and proxy server
Proxy can be a standalone server or secure tunnel. In latter case the proxy is running usually on the client device itself or on local network. E.g. Ki4a has a builtin interface for SSH login to create a Dynamic Forwarding tunnel that acts as a local SOCKS proxy. Shadowsocks and Orbot (Tor) are two more examples of encrypted tunnels. Both listen on SOCKS5 as well as transparent proxy ports. Drony and Postern can also create shadowsocks tunnels. And the list goes on.
Redirect traffic from whole device or specific apps towards proxy
Every app doesn't have built-in support to use SOCKS proxy, only a few apps such as web browsers have. So we need third party apps / native tools which use different approaches.
Two common methods are redsocks + iptables and tun2socks + VPN/routing. ProxyDroid uses first approach. In latter case root is not required because apps  (like SocksDroid, Orbot, Shadowsocks and many other firewalls / sniffers) use Android's Java VPN API. Drony and Postern use Java based similar methods. Ki4a provides both options.

See this answer for other proxification methods.

Just as a reference, Shared library interceptor is a popular hack in Linux world (used by socksify, tsocks, torsocks, proxychains etc.). When a dynamic binary is run for some network communication, LD_PRELOAD variable is used to force load a specific dynamic library in memory before any other shared libraries. Dynamic linker searches for required symbols in this library first. This library is modified to offer the same functions as the OS socket layer, but transparently translating plain connections to proxied connections by effectively taking control of functions/syscalls related to networking (socket, connect in particular). Proxifier and ProxyCap do something similar on Windows.
Though this approach is more relevant to native libraries and not Android's Java stack (where apps run), apps can be hacked to start with specific LD_PRELOAD values. Android's linker does support LD_PRELOAD, see Termux-exec for instance. But I haven't seen a practical example of this approach for proxy on Android.

SETTING SOCKS PROXY WITH CLI:
While executing both above mentioned steps through command line isn't impossible, it's too complicated to be feasible for a common user. redsocks can be configured with iptables while tun2socks requires creating a tun network interface as well as configuring RPDB / routing table (that's what VPN API does at back end). SSHuttle is also similar project that's based on SSH and makes use of iptables NAT, TPROXY or routing. ss-redir (shadowsocks) also uses iptables NAT/TPROXY. Plus, all methods require root access.
For a redsocks+iptables working example, see How to send all internet traffic to a SOCKS5 proxy server in local network?
CONCLUSION:
So to use SOCKS proxy on Android is best achieved using an app. SocksDroid is simple, free, open source and has no ads. Or you can use an app specific to a protocol e.g. Tor or Shadowsocks (I have no affiliation with any apps mentioned in this answer). But the selection depends on multiple factors like protocols / methods and one important being the UDP (particularly DNS) support.

SOURCE:

Comparison of proxifiers


text:
Why do I have to get permission to save to my own phone?
I am the owner of a new Samsung Galaxy J7 (J700T). When I try to delete files with no data on them on my internal, external, or SD card, the phone tells me I am denied.
I want the files I've created. I would love to have this phone checked for spyware, but I am a Windows desktop guy and this Android flashing/rooting stuff has me stumped. Please send me in the right direction.
How do I get my permissions to stay in my favor? How does this happen, why I don't have the authority to do what?

I think you are mixing things up. On Android permissions are not "user" based, but app based. Therefore there is no "you" which can have or have not the permission to do something. It is always the app which has the permission. Therefore you get the message that something is denied it is the app you use which misses the permission.

Related: https://android.stackexchange.com/a/208982/218526

As @Robert mentions in his excellent comment, the permission system on Android is not user-based, but app-based. Although newer Android versions have some multi-user support, the general attitude of the privilege system is that you, as the owner of the phones, have the privilege to modify the access of the apps. It is because the only human using the phone is its owner, so they can be trusted, and they is the one who should be protected from the generally distrusted apps. Before the mobile world, the case was its opposite: the apps was (roughly) more trustable, but the users using them were not.
With the default settings, in general, if you give an app access to your files (photos, documents, contacts and so on), it should work. A general "permission denied" for everything is clearly a problem. If your device is not rooted, the warranty now lives and you don't want to root / reflash it, then you might look for your warranty options.
Before that, I would suggest to try a factory reset. It might help. Considering your problem, you probably don't have data to lose with it. :-)


text:
Overlay a live WiFi camera image
I am using a WiFi endoscope camera with an Acer Android tablet, for woodturning hollow forms. The camera points to a cutter on the same structure as the camera so that the camera is always focussed on the cutter.
I need to be able to superimpose a graphic that I have created over the live image of the cutter. Essentially the image is of the cutter, but with a margin drawn around it.
I have tried many apps that allow overlaying one saved image over another, but none of them work with a live camera "feed". I found one that does allow an image to be superimposed over a live camera feed, but it will only use the camera feed from the camera on the tablet.
Can anyone here help me with this?

well that looks like a good custom app, it s possible if you are using anything above android 8.0 If you want to see a custom overlay of objects on a live feed camera ,then there is no ready made app on store , however i am working on it and could get it for you on store if you can specify , what are you looking to put and what kind of features would like to have on it?

Andre: My tablet is running android 6 and acer says that it cannot be updated. To show you what I am trying to do, here is a link to a youtube video. https://www.youtube.com/watch?v=0kYF3fgwhBs If you forward to 7:13, you will see the idea of using a camera to stream a live video while overlaying it with a graphic. I can create the graphic and save it as a .png file on the tablet. Then,  I need to be able to move and size the graphic to match the cutter live image. If this conversation is best taken off forum, you can reach me at grant4 at wilki dot ca. Thank you very much.

@gwilki Since 7:13 is the end of the video, I assume you meant 1:45? However, since you're using WiFi camera, I'd like to know how you can access the feed on Android for now (directly from browser? Exclusive app by them?), or the model of the endoscope, because  how they send the feed data might be specific and proprietary per model/brand (or in other words, there might be no generic solution that applicable to any WiFi camera).

Well, for the generic solution, there might be some apps that allow the user to overlay the whole screen on any apps and add some images/draw on it, but I haven't done any research on it...

great, I got it . This is easy and possible, SO first of all i need to know the camera you are using to record or live preview your work ?
You need a good high resolution camera , which can zoom at that detail what was shown in your Youtube link .
Secondly if the camera has live streaming / mirro link options that will be cool , cause you can connect to TV  / Mobile in android and get the camera  live streaming in you mobile or tablet.
Your tablet with android 6.0 is good enough .
The important thing is you Camera that will record / live stream when you work.
Secondly , you can do this wirelessly and wired way.
Wireless ,if you cam has a wifi direct / mirrocast , airplay like features , wired with it supports direct camera raw data to pc streaming ...
Hope this helps..

Andre: First, I'm sorry about the youtube time. I should have said 3:19. That's where my interest starts. As for the camera, I am using this one: https://www.ebay.com/itm/For-Android-iPhone-WIFI-Endoscope-Waterproof-Borescope-Inspection-Camera-8-LED/282606613184?ssPageName=STRK%3AMEBIDX%3AIT&var=581788369393&_trksid=p2060353.m1438.l2649.

The resolution is very good and its lightweight and small size is ideal for my application. It will live stream while I work. I use it wirelessly. Finally, the app that I am using to stream/record is this one: https://play.google.com/store/apps/details?id=cn.com.buildwin.YCamera3. Right now, I stream the camera input onto my tablet. Then, I tape a transparent overlay onto my tablet and trace the cutter with a sharpie. I would like to be able to do the "trace" with an app.

Andrew: My time comment was directed to you. Sorry again. I am using this setup for turning the inside of things like vases and at 3:19, Alan starts to turn a vase. The cutter disappears into the vase, but since the camera is trained on the cutter, the turner knows where the cutter is relative to the outside of the vase. The overlay feature that I am looking for is used to set a fixed wall thickness. When the overlay "touches" the outside of the live video vase, I stop turning at that spot.


text:
Make home screen rotate on Samsung Galaxy 9
Most of the apps will rotate when I turn my device. So does the screen on my tablet. However, on the phone (Galaxy 9), that doesn't happen, making usage in horizontal mode a bit awkward.
Is it possible to make it rotate and if so how?

Related/possible dupe: How can I enable auto-rotate for the home screen?

I am currently using a Galaxy S10+, and I was using a Galaxy Note 8 before that. Both phones support rotating the homescreen to landscape in their native launcher, but it is disabled by default. I am going to assume your Galaxy S9 supports this as well. Try the following:
Go to Settings > Display > Homescreen. Then look for a setting related to rotation.
On my S10+ the setting is called "Rotate to Landscape Mode" and you have to switch it ON to enable homescreen rotation.

On my Note 8, the setting is called "Portrait Mode Only" and you have to switch it OFF to enable homescreen rotation.

I'm not sure regarding the default UI settings as I use Nova Launcher myself (on a stock Samsung Note 8).  For Nova Launcher though -- root not required -- you would go into Nova Settings > Look & Feel > Scrren Oreintation and set to desired settings, such as Auto-Rotate.  I noted that the default value is set to "System Default", which does not rotate.  In the default device settings, navigating to Display > Home should be more options; for me it just launches the Nova Settings, so unfortunately I can't test it for you at this moment, but I hope that helps!
EDIT: I just tested on my spare device and found the default system launcher UI (Samsung Experience Home) does not offer a method to rotate your home screen by default.  However, if you update your OS to 8.1, the option toggle "Portrait Mode Only" should become available as an option (source).  Alternatively, if you are willing to dive in further into backend settings, you may be able to use an application like Setedit to modify it, but I need to do some more research to verify that.

I noted there was another similar post being referenced by @Andrew T., however the post is for a much older OS and it also requires root and uses a custom ROM.  In the case of this question and specific device model, I do not believe root is required (to be confirmed).

I find it surprising that the default home screen by Samsung wouldn't support such an obvious feature. Especially given that their tablets do, I suspect that it's a conscious decision for some ungraspable reason...

Quoted from an earlier answer of mine:

Ultimate Rotation Control forces any app - even those that don't
  support a certain orientation - into any orientation. It also supports
  setting on a per-app basis.

However, note that even if you could force an app to show in landscape, the app itself might not actually support it, and the layout could look somewhat messed-up or downright unusable. The aforementioned app is paid but has a free 7-day trial for you to evaluate the situation with.

I find it surprising that the default home screen by Samsung wouldn't support such an obvious feature. Especially given that their tablets do, I suspect that it's a conscious decision for some ungraspable reason...


text:
How large can a "recovery" like TWRP be?
Perhaps someone can correct my understanding.

True or false: TWRP is copied into the "recovery" directory and can be executed after reboot.
True or false: Running TWRP does not require an unlocked bootloader. (If so, why not?)
True or false: The size of a program such as TWRP is limited only by the size of the partition it is being copied into, and could be quite large.
True or false: An entire OS could in theory be run as a "recovery" if it were so desired.

You're right, TWRP is a custom recovery which is based on specific device recovery so its size would be the same as the recovery  partition

How large is that partition generally?

False. Many newer devices utilizing the A/B partition layout don't have a dedicated recovery partition. See landing page for Google Pixel for a full explanation.
True. Certain devices have exploits that allow recovery on locked bootloaders - this kind of recovery is often referred to as "Safestrap". Do note "exploits" - most devices don't have such discovered.
True - partition size is usually the same as boot. On my Xiaomi Mi Mix 2, both are 67108864 bytes, i.e. 64MB.
True - recovery can be considered a minimal OS by itself (with complete display, input, file management subsystems). If you want to start a regular OS by booting into recovery, just flash a regular boot image (one that usually goes into boot) to recovery.

+1 last point - TWRP by itself can be considered as bare bone OS in addition to letting you boot into one