text:
Will android background execution limitation issue affect Android notifications in 8.1 + devices?
Recently i have updated my device from 7.0 to 8.1 .
Will android background execution  limitation issue affect Android notifications in 8.1 + devices?
Some of the app's notifications are not showing after the update ?
IS this due to background execution limit ?

Android 8.0 Oreo ( API level 26 ) introduced two major background limits in order to preserve the device's battery life and RAM resources.

Background Service Limitations: After Android 8.0, apps which go into the background have restrictions on the use of Services. It introduces the concepts of foreground and background Services. Foreground services are visible to the users and have no restrictions imposed.

According to the docs,

While an app is in the foreground, it can create and run both
  foreground and background services freely.

Also, the system maintains a whitelist. The apps listed over the Whitelist have full access to create background services. The docs also mention that,

To migrate to Android 8.0 (API level 26), the developer replaces the
  background service with a scheduled job, which is launched
  periodically, queries the server, then quits.

Broadcast Limitations: From Android 8.0, BroadcastReceiver can only be instantiated at runtime and not in the app's manifest. This reduces the system's load as the app only uses the component when required.

The problem is described in the docs,

If an app registers to receive broadcasts, the app's receiver consumes
  resources every time the broadcast is sent. This can cause problems if
  too many apps register to receive broadcasts based on system events; a
  system event that triggers a broadcast can cause all of those apps to
  consume resources in rapid succession, impairing the user experience.

Now, your question,

Some of the app's notifications are not showing after the update? IS
  this due to background execution limit?

There can be the following problems based on the limitations described above:

The app's developer hasn't optimized the app for Android 8.0 changes.
The app does not make the use of Android Services wisely and therefore gets eliminated by the system.
The BroadcastReceiver hasn't been initialized properly as required and therefore is not operational and could not update the app content.
Some other underlying change to which the app is not optimized.

Hope this helps.


text:
Anyway to make blue light filter App include the notification swipe-down area?
From initial Googling it seems that it's an intentional issue in later Android OS versions, that blue light filters (Apps) cannot have any effect on the swipe down notification area. I was just wondering if there's any latest news or fixes on this?
For Android OS 8, non-rooted phone.

Are you referring to the blue light filter functionality in the OS or are you talking about an app providing the blue filter?

@Robert an App. Added to question

AFAIR Android 9 includes a system option for reducing blue light. Therefore on Android 9 there is need to use an app for that anymore.

The following article explains the background and that this restriction is present since Android 8 and will not be changed: https://www.xda-developers.com/android-o-is-breaking-apps-that-overlay-on-top-of-the-status-bar/

@Robert I have Android OS 8

Figured out a solution which can be ised with Moto devices that have Moto Actions. One of the features is Night Display, which is a built-in blue-light filter which covers the swipe-down notification area.

source: Stack Exchange

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

sort: votes


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Compass needle deflected when near off smartphone
It puzzles me that a compass needle is deflected when I bring it near (~ 2 cm above the screen) my turned off Android smartphone, which can only mean there is still a electric current inside it. Surprisingly, the deflection is the same with the phone turned on. What may be the reason behind it?
I could yet not verify whether the same happens with other mobile phones.

It was quite hard deciding the appropriate StackExchange site for this question. I hope I got it right.

Smartphones and tablets have magnets.
Speakers & microphones have magnets needed to operate.
There is a magnet for the vibration motor.
There may be magnets used to align wireless charging points.
See this video about magnetic paper which shows some examples of where magnets placed within electronic devices:
Physics Girl - How Magnet Paper Works feat. MKBHD

Of course! I forgot about the other obvious reason for a magnetic field: a magnet

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


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Where is the MTP and PTP option in Android 9?
Where is the MTP and PTP option in Android 9?
I checked
where is the option to enable MTP?
and it's not there.
I have a Moto G7 Power. I don't know if that makes a difference.
I see there is a command line option How Do I change from PTP to MTP mode? Cannot find options in settings
But i'm looking for the GUI option
I think they moved it from settiings..storage.  as it was there on an old phone.
I tried tapping build number 7 times, I can't see developer options.

an answer from barlop https://stackoverflow.com/questions/16596877/android-studio-doesnt-see-device/18515360#18515360 mentions that it's now in developer options
i can see developer options now, (And FWIW I turned on USB debugging).  but they moved the sectoin to MTP  from the 'input' section of developer options to elsewhere
To find the USB options now, there is a search within developer options, search for USB. Now it comes under "default USB configuration"
and you see USB controlled by, or USB preferences.. And it's there
update 2020
And if PTP is listed but not MTP, then maybe what android may refer to as "File transfer" is the same as MTP. See my comment  PTP but not MTP   , this link https://www.xda-developers.com/install-adb-windows-macos-linux/ says "file transfer (MTP)” mode"   which suggests to me that they may be the same. And BTW to install adb you probably also need the driver from the android sdk as mentioned https://windowsreport.com/windows-unable-install-adb-interface/ so you don't get a yellow exclamation mark for adb under "other devices" in device manager.

Where are the dev options on a Samsung Galaxy Table Android 9?

@user3123159 I don't think it's phone specific , you'd get them the same way on any android phone it's a bit ridiculous but these are the instructions to get it  and yeah it involves tapping an option 7 times https://postimg.cc/sQDct088


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my phone is not working. How can I get my contacts?
My phone is not working. How can I get my contacts from it? I have tried everything to get them. Drying the phone in rice. But the phone still will not work. I need my contacts.

Have you synced your contacts in any of your accounts?

first, always remove battery (if possible), and drying is best with open case at 50° degree celsius for ~ 2-3 hours. Depending on google settings, if it is completely dead, just the touch or the screen is dead, or just keys not working, phone model and encryption, there might be a solution to recover the contacts


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Network Problem in Android x86
I dual booted Android x86 8.1 iso in PC. Everything went nice but when I set it up it was not getting network. I am using USB device for internet connection. Can anyone please tell how to fix it?

An "USB device for Internet connection" is not very specific, therefore nobody will be able to help you. When writing questions be as precise as possible.

What do you mean by USB device for internet connection? Are you using a dongle with a SIM card? If so then those dongles need their respective software to connect to PC which are (in most cases) only available for Windows.
If that is not the case, try these steps.
In a terminal, type:
sudo vi /etc/init.sh

add 4 lines below to init.sh
netcfg eth0 dhcp
echo nameserver <ip> > /etc/resolv.conf
dnsmasq
setprop net.dns1 8.8.8.8

Yes, its a dongle.

There have been many discussion in the past about this topic & without a straightforward solution. There is a hack solution by first recognising the dongle under Linux to get the chat-scripts. For a detailed guide, have a read on XDA Forum: https://forum.xda-developers.com/android/development/guide-huawei-usb-3g-modem-android-x86-4-t2829533


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Is there a way to enter recovery mode without using home and volume keys?
I have a Samsung device and i need to use the Android recovery mode for some reason.As for Samsung, i have to use the volume-down and home key to enter recovery mode
But the problem is, my home key is broken and as a result, I can't use the normal way to enter recovery mode.
I can use ADB to do that with my PC but i can't do that every time when i need.
So, is there a way to do that without using the home key?

Note: My phone is not rooted and i know that i can change the recovery mode entering configuration easily if i root my phone but i don't want to root my phone.

If your device boots fully, adb reboot recovery should take you there. However, if your device is rooted, then you can use Quick Reboot in the Play Store will get the job done.
UPDATE: Due to a change in the question, the answer would be that this is not possible without root access or being able to use the buttons on the phone.

This does not answer the question, he does not ask for (pc) adb or root

@alecxs The question's parameters have changed since my answer... The answer on an unrooted device is that outside of using adb, there is no way to enter recovery on this device without use of the keys. I will update my answer.

i didn't know that, because the question has no edited state. Anyway i wouldn't say impossible, maybe there is a way with short circuiting pins via usb dongle, who knows? afaik Samsung has USB OTG support, this means it might possible to run automated adb commands from Hak5 Rubber Ducky

@alecxs True... But if the user isn't willing to root, I find it unlikely they would want to use a 3rd party piece of equipment or disassemble the device to access any contacts. I made the assumption since they did not want to root, that they wanted to do it on the device itself, in which case I stand by my answer.

@acejavelin, i didn't change my question parameters, you didn't notice that i told in my question that i know i can use pc to do it but i want to be able to do without pc.

@shiro13 Your original question did not note that root was not an option, so my original answer gave you your options. You added the part about you not having root, and not wanting to root either, after the fact. I still stand by my answer, reboot into recovery requires a privileged user account that applications cannot access directly from the device without root.

only for Download Mode, unfortunately https://www.amazon.com/Download-Samsung-Android-Smartphone-Unbrick/dp/B01HQ0DJR2

install Terminal Emulator
http://play.google.com/store/apps/details?id=jackpal.androidterm
type from terminal
reboot recovery

this one should work without root

That terminal app would provide shell access with unprivileged abilities. You need a privileged user, such as shell (user 2000), system (user 1000), or root itself.

at least, it works for me with explicitly rejected su permissions

@alecxs i want to inform you that the command didn't work.I did some digging and found that the command is actually 'su -c reboot recovery' but as you can see, it's a superuser command and i can't use that.

have tested on my mothers phone, it says permission denied. must be a bug in SuperSU or something messed up on my phone

@alecxs SELinux would be permissive on your phone when you tested but enforcing on your mother's. It's only SELinux which restricts apps from setting properties.


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how to replace android system.apk with one custom made version of it
I have created a copy of one of the main system apps(android system.apk) in which i have replaced some files to improve graphical view of my phone. is there any way to replace the two files or any other way to make changes directly to the application installed?
any advise will be appreciated.

Do you have root on your device?

yes i do have root on my device

You can copy the new apk file directly on the folder where the old apk is located.
I advise to copy it via recovery. If both apks have the same name, just replace the old one. If not, rename the new apk to have the same name as the old then replace it.
When you finish will need to clear the cache to avoid mixing up the old data with the new.
Important: Before processing with the copy/change operation, Do a backup of the old folder. It will be helpful to restore the old apk if things go wrong.


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Turning off my phone when power is disconnected
I am using Tasker to do some scheduling tasks and it is working all flawlessly. Now there is one thing where I am stuck at.
I want to turn airplan mode on and power off my phone whenever the charging turns off. For this, tasker needs the device to be rooted.
Can you guys please suggest me what are the minimal steps I need to take to make this happen (minimal modification to the system) At this point of time I dont want to use the other amazing features which rooting provides but just powering off my device and turning airplane mode on using tasker / MacroDroid.
I have two samsung tablets on which I want to make this happen. One is Samsung Tab S4 and the other one is Samsung Tab A 10.5.

Which Android versions do these devices have?

@Firelord both of these have Android Pie.


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How to fix apk not installed error in fortnite apk?
I am trying to install Fortnite on my phone. But it's saying the app is not installed. I tried on a few other phones too. It is not installing on any device I tried, but they all are actually incompatible for Fortnite. Even if it's not supported, why is it not installing? I can see many incompatible APKs installing on my device well. Is there anyway I can fix this?

According to what I have read Fortine requires an Android 64 bit OS. If your devices are all 32bit means they simply can't execute the app, because an 32bit OS can't run 64bit software (may be even your CPU does not support 64bit).

Robert, One of the devices i checked was a 64-bit device. It almost had all requirements to run fortnite except the ram. It had only 2 gb ram. But its not installing in too.Help!


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How do I decrypt files on my SD card that I encrypted
I recently encrypted my sd card on my kyocera hydro air c6745 and it won't allow me to decrypt. I want to download music but it obviously won't allow me to do that either

What did you use to encrypt it?

Open the Settings app, and select Lock screen and Security.
Scroll to the bottom and select Decrypt SD Card.
Tap Decrypt SD card to begin the process.
Enter your lock screen pin, pattern or password.
Wait for the decryption to finish - you can keep an eye on the progress in the notification panel. Make sure to keep the device charged during the process as it can take some time.

Reboot Your Phone and try again if not works.


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How to get boot.Img from Samsung tab a 10.5 sm-t595
I have been trying and failing for days to root my tablet. As far as I can tell there is no TWRP available for this device and the only way that looks possible to root it is to use magisk adb method. The problem is I can't get the root. Img file to allow me to follow the instructions. Can anyone help?
Thanks
Paul

Samsung might be tricky to root, read careful (you may need Magisk Canary release):
https://topjohnwu.github.io/Magisk/samsung
according to this thread you need to extract it from firmware, which is hard to find:
https://forum.xda-developers.com/showthread.php?t=3887848
few ROMs: http://support.walytech.com/index.php?a=browse&b=category&id=8666

Thanks for the help with this. I was hoping to do this in the same way as the second thread you posted. I have now managed to extract the boot.img, but when i try to patch it magisk manager says its unknown or an unsupported image. I can extract the .lz4 file from the tar.md5 file easily with 7zip, and lz4.exe appears to extract the .ext4 file with no problems, but when i try to get boot.img from the ext4 file with 7zip it gives a warning saying "there are some data after the payload data". I tried this with 2 different roms that are both for my build number. am i missing something here?

hope this help https://forum.xda-developers.com/showthread.php?t=2073775

Thanks again. I can explore the files the files with that tool but still no luck. I found a stock image on https://desktop.firmware.mobi/ that magisk manager can patch, but the output is. Img file and there is not option to change the patched file format. Am I missing something or should I try to zip patched boot image up myself and put it back in the apxx.tar.md5 and try to flash that with odin?

the first link is the most important. however, it seems dead, so please read this https://forum.xda-developers.com/galaxy-s10/development/magisk-root-galaxy-s10-series-t3918699

Thanks for all the help. i got this working in the end. it was easier as its running android 8.1 so no need for the recovery partition. I will try and remember exactly what worked and post an answer in case it helps somebody else

Thanks to alecxs for all the help. In the end this was possible with Magisk Manager and odin. I will try and list all the steps needed, but there was a lot of trial and error so I may miss somthing.

Get enable OEM reset then usb debugging (this will factory reset the
tablet)
Find the stock boot.img I found mine here
transfer the boot.img to your phone and install magisk manager apk
(you will have to enable installing from unknown sources)
click install magisk and choose the option to patch a boot file. Copy the
patched file back to your computer
rename the file back to
boot.img
download this tool to repackage it to a .tar.md5
file
copy the boot.img into the parts folder and try and make
the .tar file then try the .md5. if you have problems download the
latest version of cygwin64 and copy the contents from the
installation folder into the bin folder of the tar.md5 tool and try
again
now you should have a tar.md5 file containing your patched
boot.img that you can flash onto the ap partition with odin. restart
to boot loader ( hold down power and volume up or use adb command
adb reboot-bootloader and flash (there are other more detailed
tutorials on how to do this)
check to see if it succeeded. For me
it succeeded and then when rebooting it failed the integrity check
and factory reset itself. I reinstalled magisk manager and found
that it had worked. I let magisk install itself and update. I
installed a root checker and it showed i had root access

I hope this helps someone


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Google Photos search to show only local photos
On my Android phone in Google Photos, I want to select and perform an operation only on photos which are actually stored on the device.  I tried a couple of search terms such as "local" and "local:" but I am really shooting in the dark here.  Is there a way I can filter or search and only show images which are on the phone, so I can then do normal operations on all of them at once?
There are several pre-defined searches available like "Videos" but I don't see any which do what I want.

perform an operation only on photos which are actually stored on the device.

If this "operation" is outside of the "Google Photos app" you can install an other gallery app that can search local photos, has "multi-selection" and "send"
Example:

find local photos with alternative-gallery app
select the photos
send selected photos to "scrambled-exif-app" (= remove exif data from seleted photos and re-send)
send result via email

A Photo Manager (where i am the author of) is a gallery app with powerfull search functionality.
I am shure that other gallery apps can do this, too

Actually, the reason I want to do this is that I want to rename the images.  I can do this outside the app, but then in order to sync the changes to Google Drive I have to delete the photos and then re-upload them.  If I rename all the images locally in a single batch, I want to then select all the images renamed (either before or after the rename) and then "delete" them after I rename so Photos will think the renamed photos are new and re-upload them.

And yes, the fact that Google provides no native way to simply rename images is idiotic.


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Cannot add "Amazfit Bip" watch as a "trusted device"
I've got a ZTE Axon 7 phone, and it generally works fine. I also have an Amazfit "Bip" watch, and I've successfully paired it with the phone via Bluetooth. However, when I try to add the watch as a "trusted device" via the phone "Security" settings, it doesn't work; the phone just immediately tells me that it "Can't add device" even though the watch is turned on and immediately adjacent to the phone. (The watch shows up as a choice in the "trusted device" screen.)
What is it that I need to do to get the phone to pay attention to the watch as a trusted device? I've done this before with the same watch and another Axon 7 phone, and I had no problems then.

I was able to do it; I must have done this in the past and forgotten. From the "Mi Fit" app that goes with the watch, there's an option to set up security pairing. Once that's done, it works via the normal Android screen (the app sends you there).

Apparently from Android 8 onwards the Mi Fit app is not allowed to create a trusted pairing through its application and won't show up as discoverable even with that option selected.  There is a way to force it through a dev mode of some sort but I do not recommend that.


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android notification repeat
I'm using Google Pixel XL (OG) w/ latest Android OS w/ latest security update, yet noticing that Android sometimes shows me exact same notification as it showed me recently and I already swiped it out(
Please advise.

Did you get the same notifications after your restarted the device?

@ShubhamPanchal notifications repeat happens without reboot, just after I swipe out notification, exact same notification appears.


text:
Easily scroll to last page of apps
I have to scroll right 63 times from the home screen to get to the page where icons are placed for new apps installed on my phone.  Is there some shortcut to get there?  Some gesture I can enable or an icon I can put on my home page or something?
Google Now Launcher 1.4.large, Android 8.1.0, Nexus 6P
I just found a faster way to scroll through the pages.  If I tap and hold on an empty space on a page then the page will get smaller and it will scroll multiple pages at once when I swipe.

In Google Now Launcher, there is no settings that allows to go directly to the last page. And there is no infinite scroll that would have allowed you to scroll from the first to the last page.
My advice is to install another launcher (if possible).

on the bottom of my screen there is a series of dots, each representing a page of apps. Touch the rightmost dot (63 pages of apps??) and it should take you to the rightmost page where your newest apps are placed

I have the dots, but tapping them doesn't appear to do anything.


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How to keymap the key for moving to end of text file?
How to keymap the key for moving to end of text file?
Hi,
My keyboard is broken so I am remapping the keys with the otherwise interesting KeyMapper app.
However I cannot find the code for moving to the end of a text file. My text files are huge so I want to go directly to the end. Anyone know the keycode for this key? It's not just KEYCODE_MOVE_END, I have tested that and it only takes me to the end of the line, not to the end of the file.

Try to combine KEYCODE_CTRL_LEFT and KEYCODE_MOVE_END

I think the app does not allow combining.


text:
Revert system feature split-screen
I have official Android 9.0 ROM for HU PX5 GS rk3368.
However, I think is more like general question.
In my system, split-screen feature is disable (or just some apps are missing).
I tried to set enable_freeform_support 1 but that did not helped.
Note I did it by:
adb settings put global enable_freeform_support 1

That is because Developer Options are also disabled (I can not enter - probably app / Activity removed)
I'm pretty sure there is a way to fix that, but I don't have enough knowledge about Android to figure it out.
I have access to root (over adb)
EDIT 1
After executing command and rebooting I checked if it was not reset to previous value
settings get global enable_freefrom_support
It returns 1 so it is ok. However feature is still not working.
I also find out that following prop may disable spliting screen
getprop ro.config.low_ram
But it is not present in my configuration.

When you run the command, do you get an error message? If not run the command again, then reboot the device and check if the feature is enabled.

@ReddyLutonadio I have updated question


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I can't change my home app in lineageOS 14.1
I'm having problems with the home app in lineageOS. I usualy have the Nova Launcher Prime as home app in my phone but now I'm unable to use it because when I'm going to change doesn't appear a diferent app.
If it helps I have a: Vodafone Smart Ultra 6, LineageOS 14.1, Android 7.1.2.
In the picture is writen Home Aplicarion

Trebuchet is the default launcher of lineage and Cyanogen mod custom roms. Does nova launcher appears in app drawer? Open nova launcher and open Nova settings, go down and tap on select default home and try to set it as default launcher. Please reply if there's any issues.

Thanks for the help. When I open nova launcher (it appears in the app drawer) in the settings it says "Nova Launcher is not set as default click here to set". I press but then it still just appear the default launcher from lineage

Select Settings > Apps. Then select the gear. In the home app section, select Nova launcher

Again thanks for the help but the problem is that the nova launcher does not appear when I do that.


text:
Why does "adb root" do nothing?
I have a OnePlus 6T. It is rooted by TWRP and Magisk. I have set ro.debuggable to 1. But when I type adb root it does this:
C:\Users\ituser> adb root

C:\Users\ituser> adb remount
Not running as root. Try "adb root" first.

I cannot even use adb pull on system files.

I wonder it doesn't throw an error message. To my knowledge, adb root doesn't work on "production builds" (like stock ROMs, even if rooted). So unless you have a "developer ROM", chances this does anything are quite low.

On production — user build of a ROM — you can't start adbd as root unless ROM or at least adbd binary is rebuilt with required modifications. Reason is the ALLOW_ADBD_ROOT build flag (1, 2).
That's why adbd Insecure was developed, which replaced the adbd binary with a modified one.
On a userdebug or eng build (or with insecure adbd binary extracted from any of these build types):

If ro.secure=0, adbd runs as root when enabled from Settings (Developer Options) (3). However adb root won't work (4).
If ro.debuggable=1, adb root will restart adbd as root (5, 6).

However adbd can be built from modified source code to skip all these checks. Additionally SELinux should also be taken care of, if in enforcing mode. adbd must be allowed to run in unrestricted superuser context: u:r:su:s0 (7, 8), which isn't the case for user builds (9, 10, 11). See this answer for more details.
Android properties can be overwritten using /data/local.prop on userdebug/eng builds i.e. if ALLOW_LOCAL_PROP_OVERRIDE build flag is set (12, 13). But this doesn't work for ro.* properties (14) and same is true for setprop commandline tool. However default.prop / prop.default file — which could be located under multiple possible locations depending on the device build configurations (15) — can be modified to change read-only properties (if not already set from some other property file or *.rc file). If the file is in ramdisk, boot.img needs to be modified.
Magisk's resetprop tool can reset the read-only properties even if they are already set. ro.secure and ro.debuggable both may have possibly been changed as a part of MagiskHide policy (16), which you can revert back to allow adbd run as root.
Another related property is ro.adb.secure, which controls public key authentification. By setting ro.adb.secure=0 on userdebug/eng builds, authentification is skipped (no device unauthorized message ever) (17, 18, 19); related: Storage location of “adb_keys”.

As an added info, the type of build of the rom can be found looking at ro.build.type


text:
Is there a way of identifying created Users historically on a Huawei P20 Pro?
As there is the ability to create multiple users on a smart phone, e.g. the Huawei P20 Pro, I am curious to know if it is possible to view/keep track of all created Users on the download data of the phone? Or, is it that when a User is deleted, so is the evidence of that User ever being created on the device? Or, does the internal memory of the phone itself hold a record of all Users created?

Are you talking about "users" an Android level (multi-user system that allows to keep different sets of data for each installed app) or are you referring to the "Accounts" sections where you can add multiple user accounts from different services?

I'm referring to the created Users in Accounts e.g. Guest User, Bob, Jane, etc which you can switch between on the phone

you can install file manager like Total commander.
Go to File System Root
/mnt/user
Here you can find list of users created but it will not display usernames.
You will get to see, the date of when the user is created.

cheers - bourne.  will have a go a that.


text:
Is it true, that Trump sanctions as of 01.06.2019 have started battery drainage on Huawei Android mobile phones?
It is 1st of June 2019 and new round of sanctions have started under Trump. And severe drainage of battery of my Huawei Android phone has started as well. 20% of batter is gone under just 1 hour. Android System is the main user of battery - around 30%, then WhatsApp follow with 23%. Remaining apps consume less. I have pending update from Android 5.x to Android 6.x on my device but there is button to download this update and I have choosen not to do any activity. Why such unexpected drainage. Is it due to Trump?
p.s. and my Grindr application is ceased to start as well. Who knows what else will happen?

It's a google phone, everything is possible.. but funny question anyway. I guess it is related more to google play services, they sometimes release worse updates (and you can not prevent Google Play from updating itself)

Well, if Trump says "Huawei is shit", your phone might start to stink. That's what he calls "laws of physics" (or something like that). // Honestly: Why should the two be related? Asking whether it's true (no, that's bullshit): has that indeed been stated in some "fake news", and if so where?

https://kojenov.com/2020-09-15-hisilicon-encoder-vulnerabilities

No, it not because of Trump. Why? Because Huawei was granted 90 days during which it will still continue to support equipment.

The Trump administration is working to ban Huawei products from the US market and ban US companies from supplying the Chinese company with software and components. The move will have wide-ranging consequences for Huawei's smartphone, laptop, and telecom-equipment businesses. For the next 90 days, though, Huawei will be allowed to support those products. The US Department of Commerce (DOC) has granted temporary general export license for 90 days, so while the company is still banned from doing business with most US companies, it is allowed to continue critical product support.

Even if it was not granted an extension period, I don't see how suddenly the battery will start draining.
By the way, Huawei and Google are still working together on security issues during the 90-day exemption

The 90-day license means Google can work with Huawei again on smartphone updates. A Google spokesperson told CNBC, "Keeping phones up to date and secure is in everyone's best interests, and this temporary license allows us to continue to provide software updates and security patches to existing models for the next 90 days."

From the second listed source:

Existing owners of Huawei smartphones can continue to enjoy Google apps and services, such as Google Maps, Gmail and YouTube. They can still use the Google Play Store and receive security and software updates for Google apps and services.

Existing Huawei smartphones, like the recent Huawei P30 Pro, will continue to have access to Google apps and services, as well as security updates. But Huawei may not be able to update the Android software to the next version promptly, if at all.
Since most Android smartphone makers, such as Samsung, take months to update the Android software with the latest features, consumers may not be overly concerned about this.

In mid August, if the exemption is not renewed, your battery will still work fine (assuming it is not old or damaged already).
Check your running services and processes to find out what is causing the battery to drain.
You question will be great at Skeptics StackExchange.
Source:

The US DOC gives Huawei a 90-day window to support existing devices
Huawei barred from Google updates: What you need to know if you own a Huawei or Honor phone

I have Huawei P9, been going grand for a few years, I kept it on old Android version, heavy ish use though loads of apps installed battery would last a day, less if I had maps/gps route tracking.
Tuesday this week 25/6/2019 quite inconveniently big battery drain started happening. Google Play Services listed as top user along with Android OS. I did a big cleanup, got rid of some big apps, got rid of an unused account, tightened up on apps, upgraded OS.
Then finally disabled automatic app updates.
This seemed to stop the battery drain!
The OS upgrade has changed look/feel but has made phone have faster response which is also a good thing.

This is just political nonsense. Awaiting the day rest of world is bleeding out of rare earth minerals now, china has the monopol..  good by apple, hello huawei :D Check your background data usage, then you will know who is leading the war of data gathering. Delete Instagram Facebook and WhatsApp, this will really save your battery (and privacy)


text:
I cannot open or play songs with anything but Files (default file explorer on Android One)
I have a new Nokia 3.1. After putting in and formatting an SD card, I copied a tonne of music to it (in /Music in the root folder). These are m4a and mp3 files. It seems only default apps can see and play music - although not very effectively since I don't want to pay or use the internet to listen to my own collection.
Every music player app I get (Musicolet, Pulsar, etc.) will not find the music automatically; will not find it when forced to rescan; will not play it when it is sent to the app via Files.
'Files' and 'Google Play' will see and play the files. Musicolet (the only one out of 10 different apps) will scan the files, pick up that they're all there - and then not update the music library or show anything.
I've tried clearing temporary storage, uninstalling/reinstalling music player apps, restarting the phone - the same story.
What is going on?

Android uses a media database ("Android MediaStore Database") which is used by most apps. If the file has not been indexed by the database or is unknown to the database it doesn't exists for the apps.
If you have copied a "tonne of music" this database may be a bit overloaded by indexing all the uploaded music files (or may be even crashed).
Therefore I would first wait a while and then re-check if the media files are now visible in the player apps. If after some hours the files are still not visible, reboot the device. This usually triggers a re-scan of the media files.
Furthermore the actions I presented at the end of this answer also can be applied in your case.


text:
Adb pull - access denied
I want copy all files(including system files),
but when I enter adb pull /
i get this:
I tried entering adb root but that does nothing.

Is there any fix to this?
Else any other way to copy all files(including files like /data) to my pc?
PS:I have rooted my phone(OnePlus 6t) and have twrp and magisk.
Thanks

Comments are not for extended discussion; this conversation has been moved to chat.

To (re-)enable adb root you have to modify your prop.default file. This file was traditionally named default.prop and stored inside the ramdisk of boot.img - however, for system-as-root devices it is inside /vendor.
change the line ro.build.type=eng into:
ro.build.type=userdebug

from the Magisk Troubleshoot Wiki:

ADB cannot run as root in production builds
If you're having issues running the ADB root command after installing Magisk this is because of MagiskHide setting a few prop values to known "safe" values. You can get ADB root working again by turning of MagiskHide and rebooting, but if you need MagiskHide for some app or service this could quickly become annoying.
A more convenient solution is to reset ro.build.type and ro.debuggable to their original values (userdebug and 1 respectively). This can be done by using the Magisk resetprop tool (see the Magisk Documentation for details), either by running it directly in a terminal emulator, in a late_start service boot script, or by using the MagiskHide Props Config Magisk module's "Edit MagiskHide props" function.


text:
Encryption unsuccessful
I am a senior citizen with very limited tech knowledge.  I woke up this AM with the encryption unsuccessful error notice on my Android.  I have been searching all these sites for help and cannot understand the "lingo". (bootloop, twrp, etc.)  Can someone tell me EXACTLY what to do?  Should I just push the "reset phone" button?  What will happen then?  Will I really lose everything?  By "losing everything" what does that mean?  Can I still make phone calls, see my pictures, play games?

You should edit your question and provide more details: What phone or tablet model are you talking about? Do you know which Android version is running on your device? Have you set a PIN/password and is the device encrypted? A screen-shot may be taken by a second cam or phone would also be good to have.

@Robert i don't think this matters. from this point there is no return. If this message appears you already lost everything

@alecxs That is not true. I had a similar message on my old encrypted Moto G after every OS update. Just another reboot and everything was fine again. In my case it seems to be a timing problem that only occurred after an update. Therefore I would never directly erase the phone.

do you mean decryption unsuccessful or encryption unsuccessful

This is caused by an attempt to Encrypt the Data partition failing.
Usually it fails from corrupt storage, and also from power loss.. did you unplug it while the encryption was in progress ?
The Wipe Everything option refers to everything that is specifically stored on the devices internal storage and data partition.
The SIM Card contacts will not be removed, however the device's locally stored contacts will be deleted.
The Files, ( photo's, documents etc.. ) that are stored on the External SD Card, will also Not be wiped, however any photo's taken and stored to the infernal storage will be wiped in the process.
No you will NOT lose access to features like calling, it will only remove the personal files you have created.
It should say "Factory Reset" to clarify what happens, but the warning is very basic and designed just to show you a problem occurred while encrypting.


text:
How to turn off ultra power saving mode that was enabled for Huawei Android while it was on low power?
My Huawei Android was on low power and it proposed to turn on ultra power saving mode. I accepted it. Now I have connected the phone to the charger but I can not enable other power modes. I am going to "Settings - Device - Power Saving" and there 3 modes are presented to me: 1) Ultra; 2) Smart; 3) Normal. The Ultra mode is enabled and I can not enable the other modes. When I try to enable other modes, the message appears and nothing happens:
This function can not be used in ultra power saving mode

So - is there way back to the normal power saving mode? I tried to Google this and some suggest to reset the phone to the factory settings. It is something incredible. There should be simple way out of this!? Why the ultra power saving mode is so protected?

Simple restart of the phone automatically brought me back to the normal power saving mode. It was that simple. That is why, possibly, no further explanation is given on the net about turn of the ultra power saving mode.


text:
2019: Can Google Assistant send a message from lock screen?
I'm looking for a way to allow Google Assistant's speech-to-text to send a message while phone is locked, preferably only to certain contacts and without being able to read past messages.
I've googled and all solutions seem no longer valid.

Did you find your answer?

@helper Not the ideal one, with the ability just to send.

Yes you can, by using smartlock.
It should be located under security and lock screen.
Click on smart lock then voice match and turn on:
Access with voice match
And lock screen personal results.
However this may let you read earlier messages and will not restrain it to only selected contacts


text:
What is Firebase App Indexing Under Google Services Settings
Where do all these data go?
Is this a privacy issue?

Here it is. It's very intrusive !

Firebase allows developers to mobile and web apps that provide a database, analytics, cloud messaging, authentication and more without the need of sever side functionality. It belongs to Google.
From Connect to Firebase:

Firebase is a mobile platform that helps you quickly develop high-quality apps, grow your user base, and earn more money. Firebase is made up of complementary features that you can mix-and-match to fit your needs, with Google Analytics for Firebase at the core.

The indexing is the database collecting  apps' information that will later be analyzed (apps that installed on the device that use Firebase API): user interactions with the app, what they click, see, etc.

Where do all these data go ?

They are stored on Google cloud stores.

Is this a privacy issue ?

Yes, it can be a privacy issue when the apps using the Firebase API collect too much information that are not related to the app's main purpose. Don't give too much permissions to apps. If necessary, write to the developers to ask why they need certain permissions for their app(s) (if they did not list or elaborate on their Google Play Store page).
Firebase documentations are found here.

Thank you so much for answering. Do you know how to get rid of this ?

It is very intrusive. See the screenshot that I added.

@TheBeatles See this link


text:
app or widget or other solution for turning just cellular radio off/on
I recently acquired an umidigi one with android 8.1 oreo naked/stock image in place and voice over wifi as well as voice over lte support.
When device is in location with wifi connection, which is most of the time, i want quick way to disable cellular radio to force a voice [ and text ] over wifi connection to be established and to conserve battery power that would be otherwise expended on the cellular radio at these times.
Currently i am accomplishing this by selecting airplane mode and then re-enabling wifi to leave me with just cellular radio turned off thus forcing the voice [ and text ] over wifi connection to be setup.  Its a cumbersome two step process and a three step process if i also want bluetooth radio enabled at these times.
Its unfortunate that the drop down menu "mobile option" doesn't turn off cellular radio voice as well as data services instead of just mobile data services.
Also would be nice to have a configuration option that would tell phone to establish voice [ and text ] over wifi if wifi connection is present and only resort to voice over lte or 3g/2g gsm connection in the event that wifi is not present as opposed to now where it does the reverse and only uses voice [ and text ] over wifi when cellular options are not available.

From my experience keeping a Wifi connection alive costs more energy than keeping a cellular connection  alive (with medium to good coverage). Permanently scanning for Wifi networks, and connecting to them requires a lot of power. Cellular network cells are much larger and require therefore more seldom any data traffic and they support hand-over.

Well you can always use Tasker.
More information on how to use tasker at: https://tasker.joaoapps.com/userguide/en/index.html


text:
Root Huawei Honor 9 Lite without screen access
Is there a way to root the device without access to the screen itself (which is broken). All methods I've seen require access of device to allow rooting etc. I need some hack into the device, whilst connected to Mac or pc - need some pointers to info about that etc.
thanks in advance (finally got time to figure this out after a year of it being on a shelf)
Charlie

In short - No, there isn't
Assuming you have previously unlocked bootloader (with unlock code from Huawei, which they don't provide anymore), there is still the encryption problem.
But your bootloader is locked, that means there is no hack into data partition.
In case you get TWRP booting from fastboot (which you don't), you could root /system and enable USB-debugging from TWRP, then remote control the device with scrcpy

You can try general unlock code, but this will ERASE data (in case unlocking is successful, which afaik only works for < 2014)
fastboot oem get-bootinfo
fastboot oem unlock UUUUUUUUUUUUUUUU


text:
Remote control of Android from PC or another Android device
Is there a way s.t.:

Whenever SMS with specific keywords are received, that those are then forwarded through SMS to another mobile ?
Or, whenever SMS with specific keywords are received, that those are then forwarded through one's configured gmail account, to another gmail account ?
Whenever the battery of the phone falls below a certain threshold, SMS or email is sent to another mobile ?
One could change settings (such as enable/disable mobile-data or location) for an Android device, remotely by sending it an SMS with certain pattern ?

Of course, when this service is being setup on the target device the device owner explicitly authorizes such change.
The usecase is where the target mobile device (Android phone) is operated by someone who is in the 2nd stage of Alzheimer's disease, stays in another part of the country. The above facility if possible would help providing some remote assistance to the person, and help sort out any issues they may have with banks and other establishments.

This questions are better placed in MacroDroid Forum https://www.tapatalk.com/groups/macrodroid

This can most likely be achieved with an automation tool, see e.g. our tag wikis on automation, tasker and macrodroid while waiting for matching recommendations.

Yes this did used to be possible, it is still possible but it requires more on the target device these days.
On below Android 5.0 , it was easy to do what you're saying, however it started to become apparent very quickly that the majority of people did not use this for its intended purpose...
For example, you could previously check on elderly people's movement's around the house to help ensure they're safe... however people would use these features on their partner's to "see" if they're Cheating for example..
It was seen as a serious violation of peoples privacy, and therefore certain measures have been implemented since above Android 4.4.
The new measures are,
• 1 single SMS application is aloud to recognise OutGoing SMS, Incoming SMS is not restricted because of SMS Verification or ( 2FA ) ..
• Real Time Permission Acceptance
• OnBoot restrictions on some devices
You did used to have Full Control over Android 4.4+ .. You could even have the application hidden with another name and icon, and Only launchable by dialing a phone number.
.
Yes you can still bypass everything, but it is very annoying to do..
 .
You would need a permission acceptance screen to accept All permissions on the first start... An OnBoot listener to start the service On Boot... and also you would need to be running as a Device Administrator to Toggle things like Airplane Mode..
The wide selections make the application very obvious to the user, so as long as you are the user on both device's, you should not have any problems.
Using applications like
• SMS Forwarder
• SMS Controller
• Tasker
and others..
I have attempted building this myself, however it has very limited control.
You can also use this Pre-Built SMS Control App..
It is released under MIT License, so you could modify it to do what you want.
SMS Control - F-droid.org


text:
How to activate time left notification in Google Family Link?
I installed the Google Family Link app on my kid's phone, mainly to limit his screen time.
He asked me to be notified before his time is running out but I can't find a way to activate such a notification.
Is there a way my son can tell how much time he has left to use his phone?

Possibly related:  "Showing how much per-app screen time allowance is remaining, on a child device running Google Family Link".


text:
How to disable "save password to Google?" prompt?
I am currently using a Galaxy Tab A 2016 on Oreo and the above prompt pops up everytime I log in an app. Is there a way to disable this prompt?
Thanks.

FYI, for future readers, I believe the correct way to disable this feature is by going to:
Settings > General management > Language and input
Then, under "Input Assistance," set "Autofill services" to "None."

This is the correct answer post 2019. However, the path to "autofill services" can vary. If a person cannot find the service, try using the searchbar in settings to find "autofill services".

This answer addresses keyboard autofill features, but does not answer the question regarding the prompt as described. YZN3RF's answer is correct. https://android.stackexchange.com/a/233168/158516

For me on a Moto G9 with Android 10, the following worked:

"Settings" > "Accounts"
Tab the main account for the phone
"Google Account (Info, security & personalization)"
"Security" Tab > Scroll all the way down > "Signing in with Google" > "Password Manager"
Tab the cogwheel in the top right > Disable "Offer to save passwords"
Voilà

In my special case I had some extra steps, because I was not able to access the "Password Manager" because I apparently used it at some point and would have needed my "Google Sync Passphrase" to get to the password manager.
Therefore I first had to head over to https://chrome.google.com/sync in Chrome, login with  my Google account, scroll all the way down and hit "CLEAR DATA" (which does reset all sync data, including bookmarks etc.).
Edit:
Discovered another setting! Right above "Password Manager" there is "Signing in with Google" which has a "Google Account sign-in prompts" setting ("Allow Google to offer a faster way to sign in with your Google Account on supported third-party sites").

On Android 11 devices method to disable saving user/password autofill prompts:
System settings -> General Management > Autofill service -> None

I found the answer after some exploration. Giving a gist,

You need to modify the Google Account Settings and modify the "Offer to save passwords" options.

Follow these steps:

Go to https://myaccount.google.com/security
Sign in with your Google Account.
Go down the page and you will see a "Password Manager" option. Click it.
The "Password Manager" is opened. Tap on the Settings icon ( a gear icon on the top right ).
The Password Options page will open. The first option you see is "Offer to save passwords".
Uncheck the option and its all done!

I tried the above and it is already off.

Then the dialog must have been disabled by default. No other setting is provided by Google to perform this action.

These instructions don't work. As @iLW, in my case the setting is already off for the Google account that I use with Android.


text:
Laptop webcam works with BlueStacks but not with Nox
I have an MSI laptop with an integrated webcam and I need the camera to function using Nox Player. I've read everywhere that the camera is supposed to work out of the box with Nox. However, it doesn't.
I installed BlueStacks to check and it worked with BlueStacks.
On Nox, whatever app I install, it acts as if there is no camera.
How to fix this?

MEMU is suspect and is "not safe" to use in my experience, and my camera has sync issues with that emulator that messes up my apps and network settings.
My understanding is the latest NOX version uses Android 7. The webcam at this time is not supported.
That's all the info I can find on this. And sadly, BlueStacks records me sideways.

For fixing the Camera sideway problem in some apps in the BlueStacks, open the BlueStacks settings, then Display and then select a portrait view or a custom resolution with the same width and height pixel.

Install "CPU X" app on Nox, then go to "Camera" menu and back. that's all.
It may correct your problem.

'CPU X' is nice tool but it is not a solution for this question.

You can try ManyCam. ManyCam comes with additioanly several features. For example: It can be reflect desktop screen in camera for Qr code read process.

So I gave MEMU a try, and it has all Nox features + the camera works.
MEMU is an Android emulator very similar to Nox Player. Installation is straightforward, nothing special is needed, and the camera works out of the box.


text:
How does Magisk work?
Magisk is known as a “systemless” root method. It’s essentially a way to modify the system without actually modifying it. Modifications are stored safely in the boot partition instead of modifying the real system files.
I have looked around but did not find a sufficient explanation as to how it actually works. How is the root access gained and maintained? What exactly is the role of the boot partition and if it integrates with the system partition how it does it?
A really detailed description of how it works lacks from everywhere I searched so it would be really highly appreciated.

Most part of your question is covered in Magisk Documentation. I will quote one of my previous answers to a different question, with some unnecessary details :)
PREREQUISITES:
To have a comprehensive understanding of how Magisk works, one must have basic understanding of:

Discretionary Access Control (DAC)
User identifiers ([ESR]UID), set-user-ID
Linux Capabilities (process and file) which provide a fine-grained control over superuser permissions
Mandatory Access Control (MAC)
SELinux on Android
Mount namespaces, Android's usage of namespaces for Storage Permissions
Bind mount
Android boot process, partitions and filesystems
Android init services (the very first process started by kernel)
*.rc files
Structure of boot partition (kernel + DTB + ramdisk), Device Tree Blobs, DM-Verity (Android Verified Boot), Full Disk Encryption / File Based Encryption (FDE/FBE) etc.

WHAT IS ROOT?
Gaining root privileges means to run a process (usually shell) with UID zero (0) and all of the Linux capabilities so that the privileged process can bypass all kernel permission checks.
Superuser privileges are gained usually by executing a binary which has either:

set-user-ID-root (SUID) bit set on it

This is how su and sudo work on Linux in traditional UNIX DAC. Non-privileged users execute these binaries to get root rights.

Or File capabilities (setgid,setuid+ep) set on it

This is the less common method used.
In both cases the calling process must have all capabilities in its Bounding Set (one of the 5 capabilities categories a process can have) to have real root privileges.
HOW ANDROID RESTRICTS ROOT ACCESS?
Up to Android 4.3, one could simply execute a set-user-ID-root su binary to elevate its permissions to root user. However there were a number of Security Enhancements in Android 4.3 which broke this behavior:

Android switched to file capabilities instead of relying on set-user-ID type of security vulnerabilities. A more secure mechanism: Ambient capabilities has also been introduced in Android Oreo.
System daemons and services can make use of file capabilities to gain process capabilities (see under Transformation of capabilities during execve) but apps can't do that either because application code is executed by zygote with process control attribute NO_NEW_PRIVS, ignoring set-user-ID as well as file capabilities. SUID is also ignored by mounting /system and /data with nosuid option for all apps.
UID can be switched only if calling process has SETUID/SETGID capability in its Bounding set. But Android apps are made to run with all capabilities already dropped in all sets using process control attribute CAPBSET_DROP.
Starting with Oreo, apps' ability to change UID/GID has been further suppressed by blocking certain syscalls using seccomp filters.

Since the standalone su binaries stopped working with the release of Jelly Bean, a transition was made to su daemon mode. This daemon is launched during boot which handles all superuser requests made by applications when they execute the special su binary (1). install-recovery.sh (located under /system/bin/ or /system/etc/) which is executed by a pre-installed init service flash_recovery (useless for adventurers; updates recovery after an OTA installation) was used to launch this SU daemon on boot.
The next major challenge was faced when SELinux was set strictly enforcing with the release of Android 5.0. flash_recovery service was added to a restricted SELinux context: u:r:install_recovery:s0 which stopped the unadulterated access to system. Even the UID 0 was bound to perform a very limited set of tasks on device. So the only viable option was to start a new service with unrestricted SUPER CONTEXT by patching the SELinux policy. That's what was done (temporarily for Lollipop (2, 3) and then permanently for Marshmallow) and that's what Magisk does.
HOW MAGISK WORKS?
Flashing Magisk usually requires a device with unlocked bootloader so that boot.img could be dynamically modified from custom recovery (4) or a pre-modified boot.img (5) could be flashed/booted e.g. from fastboot.
As a side note, it's possible to start Magisk on a running ROM if you somehow get root privileges using some exploit in OS (6). However most of such security vulnerabilities have been fixed over time (7).
Also due to some vulnerabilities at SoC level (such as Qualcomm's EDL mode), locked bootloader can be hacked to load modified boot / recovery image breaking the Chain of Trust. However these are only exceptions.
Once the device boots from patched boot.img, a fully privileged Magisk daemon (with UID: 0, full capabilities and unrestricted SELinux context) runs from the very start of booting process. When an app needs root access, it executes Magisk's (/sbin/)su binary (worldly accessible by DAC and MAC) which doesn't change UID/GID on its own, but just connects to the daemon through a UNIX socket (8) and asks to provide the requesting app a root shell with all capabilities. In order to interact with user to grant/deny su requests from apps, the daemon is hooked with the Magisk Manager app that can display user interface prompts. A database (/data/adb/magisk.db) of granted/denied permissions is built by the daemon for future use.
Booting Process:
Android kernel starts init with SELinux in permissive mode on boot (with a few exceptions). init loads /sepolicy (or split policy) before starting any services/daemons/processes, sets it enforcing and then switches to its own context. From here afterwards, even init isn't allowed by policy to revert back to permissive mode (9, 10). Neither the policy can be modified even by root user (11). Therefore Magisk replaces /init file with a custom init which patches the SELinux policy rules with SUPER CONTEXT (u:r:magisk:s0) and defines the service to launch Magisk daemon with this context. Then the original init is executed to continue booting process (12).
Systemless Working:
Since the init file is built in boot.img, modifying it is unavoidable and /system modification becomes unnecessary. That's where the systemless term was coined (13, 14). Main concern was to make OTAs easier - re-flashing the boot image (and recovery) is less hassle than re-flashing system. Block-Based OTA on a modified /system partition will fail because it enables the use of dm-verity to cryptographically sign the system partition.
System-as-root:
On newer devices using system-as-root kernel doesn't load ramdisk from boot but from system. So [system.img]/init needs to be replaced with Magisk's init. Also Magisk modifies /init.rc and places its own files in /root and /sbin. It means system.img is to be modified, but Magisk's approach is not to touch system partition.
On A/B devices during normal boot skip_initramfs option is passed from bootloader in kernel cmdline as boot.img contains ramdisk for recovery. So Magisk patches kernel binary to always ignore skip_initramfs i.e. boot in recovery, and places Magisk init binary in recovery ramdisk inside boot.img. On boot when kernel boots to recovery, if there's no skip_initramfs i.e. user intentionally booted to recovery, then Magisk init simply executes recovery init. Otherwise system.img is mounted at /system_root by Magisk init, contents of ramdisk are then copied to / cleaning everything previously existing, files are added/modified in rootfs /, /system_root/system is bind-mounted to /system, and finally [/system]/init is executed (15, 16).
However things have again changed with Q, now /system is mounted at / but the files to be added/modified like /init, /init.rc and /sbin are overlaid with bind mounts (17).
On non-A/B system-as-root devices, Magisk needs to be installed to recovery ramdisk in order to retain systemless approach because boot.img contains no ramdisk (18).
Modules:
An additional benefit of systemless approach is the usage of Magisk Modules. If you want to place some binaries under /system/*bin/ or modify some configuration files (like hosts or dnsmasq.conf) or some libraries / framework files (such as required by mods like XPOSED) in /system or /vendor, you can do that without actually touching the partition by making use of Magic Mount (based on bind mounts). Magisk supports adding as well removing files by overlaying them.
MagiskHide: (19), removed in v24.0 (64)
Another challenge was to hide the presence of Magisk so that apps won't be able to know if the device is rooted. Many apps don't like rooted devices and may stop working. Google was one of the major affectees, so they introduced SafetyNet as a part of Play Protect which runs as a GMS (Play Services) process and tells apps (including their own Google Pay) and hence their developers that the device is currently in a non-tampered state (20).
Rooting is one of the many possible tempered states, others being un-Verified Boot, unlocked bootloader, CTS non-certification, custom ROM, debuggable build, permissive SELinux, ADB turned on, some bad properties, presence of Lucky Patcher, Xposed etc. Magisk uses some tricks to make sure that most of these tests always pass, though apps can make use of other Android APIs or read some files directly. Some modules provide additional obfuscation.
Other than hiding its presence from Google's SafeyNet, Magisk also lets users hide root (su binary and any other Magisk related files) from any app, again making using of bind mounts and mount namespaces. For this, zygote has to be continuously watched for newly forked apps' VMs.
However it's a tough task to really hide rooted device from apps as new techniques evolve to detect Magisk's presence, mainly from /proc or other filesystems. So a number of quirks are done to properly support hiding modifications from detection. Magisk tries to remove all traces of its presence during booting process (21).

Magisk also supports:

Disabling dm-verity and /data encryption by modifying fstab (in ramdisk, /vendor or DTB). See How to disable dm-verity on Android?
Changing read-only properties using resetprop tool, Modifying boot.img using magiskboot and Modifying SELinux policy using magiskpolicy.
Executing boot scripts using init.d-like mechanism (22).

That's a brief description of Magisk's currently offered features (AFAIK).

FURTHER READING:

How does SuperSU provide root privilege?
How to manually root a phone?
Android Partitions and Filesystems
Android Boot Process
What special privileges “/system/xbin/su” does have w.r.t. root access?
What sepolicy context will allow any other context to access it?

This is one of the most well written answers I have ever read on here. Only one thing: What do you mean by 'A/B devices'? Is that term explained in one of the previous links?

@SteffenWinkler A/B devices have 2 partition slots to boot from: https://source.android.com/devices/tech/ota/ab/

Fascinating! Was your first link meant to be here?: https://topjohnwu.github.io/Magisk/details.html

Magisk provides root access by providing a working "root" binary mounted at /sbin/magisk. Any application that tries to run this binary will bring up Magisk to grant them root access, which is in turn managed and maintained by the Magisk Manager application.
The /boot partition is a separate partition that stores some data required to boot the system. It includes initialization of some very low-level mechanisms like the Linux kernel, device drivers, file systems etc, before the upper-layer Android OS is brought up. It is separated in a way such that Linux-level stuff is stored in it while Android-level stuff (SystemUI, Settings etc.) is stored in the /system partition. Modifying /boot does not count as modifying /system, the latter of which is what DM-verity and AVB usually checks.
And Magisk patches and integrates itself into the /boot partition, so it doesn't touch the system partition at all. It uses a technique called "a bind mount" to change the content of system files that other programs see, without actually modifying the underlying filesystem beneath the system partition (so "real" files are left intact).


text:
How to disable the google app in android 8.1.0?
I have been looking for the option using the google app itself, but when selecting  the settings button inside,  it does nothing, only stays in the same screen without the options in the second and third panel.
So I dont know how to delete the bar on the main screen.

UPDATE
Besides the method that changes the launcher (that I havent tested yet), all the methods suggesting to disable google app or google search does not work because it does not uninstall or force the stop of the google app/google search inside the installed apps. So the idea its changed to how to disable google app in oreo 8.1.0.

Just use another launcher?

Click and hold on the bar and drag it toward the the trashbin or remove text.
If that does not work then check out this article https://www.androidpit.com/how-to-remove-the-google-search-bar-from-your-android-homescreen

This was my first try and it does not highlight the bar nor appears the remove or trash option. I'm reading the article you suggested.


text:
what would happen if there as a rooted device from the factory?
Would it be feasible to see some manufacturer of devices launching a device that comes rooted from the factory?
If the user of said device accepts the responsibility and the power of getting a rooted device would that work?
Who can be against such products?
Would Google care about it?

the whole security concept is based on user accounts (each app is a user) - basically every app developer is against manipulating their stuff from root (especially banking apps)

The problem with shipping rooted device by default is that it may increase the load of customer support for the device manufacturer and possibly on other user support forums. If the manufacturer are willing to accept that, then there's really nothing really bad with shipping rooted device by default.
Google really wouldn't care about it. They may have their concerns based on security risks, but ultimately if the user is willing to accept the responsibility and risks, they shouldn't have any issues with it. The extent of Google's objection to this is that they may reject the device as non compliant according to Android Compatibility Document and therefore refuse the device from running Google Play services. It probably would be possible for manufacturers to side step this issue and still comply with the Compatibility Test Suite (and therefore eligible for Google Play), by allowing the user to easily switch root mode in developer setting, like CyanogenMod did.
The application vendors that would be the most staunchly against such this would definitely be vendors that uses and develops DRM applications and media. Their business model relies on hijacking the user's device to prevent the user from having full control of their own device.
Regular application vendors shouldn't have problems with it. They may have concerns if the security of their apps depends on the restrictions their apps will not be able to protect the user's data properly. Ultimately though, since applications vendors manages user's data, if the user is ok with it and the user accepts the risks and responsibilty, they shouldn't have any real objections.
The companies that may be wary of preinstalled root are companies that requires that their employees installs a device adminstrator service in their devices. They may simply decide to ban such device from being used in their company network.


text:
Keep android phone off until I press combination of volume + power
I'm using Asus Zenfone Max Pro M2 running on android pie.
My problem is there's kid at my home and he play with phone though it is protected with pattern he start all options from navigation bar or power off phone.

First I want to block notification bar completely I won't it scrollable.
Second I want kid prevent from turning phone switch off.

So how can I make my phone won't wake up or screen on until I do something special?

Protect it with a PIN or password.

i think the question is about not showing any wake up reaction (including not showing lock screen)

Your best and only bet is to root the phone. There may be an xposed package that will be able to give you the functionality you want. Look into the Magisk platform. I wasn't able to find a package for it but that does not mean it doesn't exist.
As far as on startup or shut down, what you described is impossible. That's controlled by the phone bootloader and cannot be changed. Attempting to do so can destroy the phone permanently.
Note that any of these procedures will void your warranty.

rooting will violate my phone's guarantee.

@Swapnil well, yes. Changing hardware behavior requires root. Otherwise what you want is impossible.


text:
What could be lowering my ringer volume every day?
I have a new Pixel 3.
Just about every day, I find the volume of the device is quite low.
I turn it up, only to find it on a low (20%) setting the day after.
What could be resetting my volume to this low setting every day?

don't touch it for 24 hours then check again

Although not the ringer vol. but in my case i find my media volume gets lowered even i increased it to full yesterday.

Do you adjust the ring volume by the volume buttons?

I think the answer is the Insight Timer meditation app.
It switches the phone to Do Not Disturb while a timer is activated, but also for some reason puts it on vibrate (a separate setting) and also lowers the ringer volume. I contacted their support.


text:
Can not select secure screen lock option on Samsung Galaxy s8+
I am trying to set my screen lock to pattern/pin/password but it reverts back to a non-secure option (swipe/none).
I have tried:

Clearing cache
Clearing credentials
Removing Nova-launcher

I'm all out of ideas.


text:
Should I be worried about a security breach if Google Maps incorrectly shows that I drove over 650 miles from home?
I was shocked to discover that this past month Google Maps shows that I was home one day, drove from a neighboring location over 650 miles to Chicago the next day, and was home the following day.
Could this indicate that someone cloned my phone?
I know that inaccuracies can occur locally, but 650 miles? And Google Maps even shows the route that I allegedly took.
I searched for similar questions. Either they did not address this particular question or they were tagged as having already having been answered. If someone thinks that this question has already been answered, then please have the courtesy of providing a link in the comments.

You don't really need someone to clone the whole phone to make this, only your Google account is needed. So, the question is, was someone logged in with/using your Google account on that day and driving through that route? Is your car (Android Auto) logged with your account and someone drove it?

The only connection between my phone and car is via bluetooth. I have concluded that my Android tablet, which only connects via AT&T fixed wireless internet caused the event. Google Maps currently thinks that my desktop computer is 400 miles away in Summit, MS. Tomorrow, it may think that it is in Colorado. So I suspect that Google Maps picked up a location of Chicago and constructed a hypothetical route that I would have taken to get there. So now, I am less freaked out.

Recently, I read of an incident in which someone's phone had been temporarily transferred to different SIM card by a scammer. The person contacted his carrier, thinking it was a technical problem. But when he got his phone working again, he discovered that his investment account had been emptied by a six-figure amount. So when I saw that Google Map route from near where I live to Chicago, I kinda freaked.

In my case, the solution was to turn off location services on my Android tablet. Google Maps was using my ISP to guess my location.
Although I was in Alabama, my ISP was reporting my location as Chicago, so Google Maps assumed that since I was in Alabama one day (according to my cell) and in Chicago the next (according to my Android tablet), then I must have driven to Chicago (even though my cell was still in Alabama). Then it produced a likely route that I would have taken. Note that I seldom use my Android tablet and that the Chicago thing occurred when I first turned it on after changing ISPs.
This is the best explanation I can come up with.
So if your location service comes from your ISP rather than your cell provider, make sure that your ISP gives an accurate location for you.


text:
how to use downloaded firmware from firmware Finder
I have jsnL21 C432 4/64 version
I upgraded my phone by 3 button method from 8.2 to 9.0.1.158. Using Firmware Finder, I found a newer version of my firmware in 9.0.1.162 which has a lot of improvement and battery optimization. I want to flash it on my device. I downloaded the firmware but it has 2 files:

Update.zip 2.24GB
Update_full_jsn_l21_hw_eu.zip 643MB

I know I should extract update.app into dload folder but the problem is I have 2 zips and inside of each files has a separated Update.app. How to upgrade with these files?
Firmware Finder

You you are talking about third party apps and software like "firmware finder" you should provide a link to the software. Please edit your question and update it with this information.

yeah sure i did that

Have you read and act on the "Important notice" in the app description?: Before do anything with your phone i request you, read XDA or 4PDA threads about your phone and how install firmwares or go to telegram chat and give your question.

yeah i read that but its nothing there :| about 2 files its just a instruction to do it with 1 file

You must use both files to update your device.
First use Update.zip which is the full firmware image, then Update_full_jsn_l21_hw_eu.zip which is the data file.


text:
How to find unused applications
I want to uninstall unused applications.
BTW : I don't have goople playstore installed nor use a google account, I use yalp or aurora stores to install applications.
How can I find the unused applications that are installed on my smartphone ?

Android since 5.0/6.0 contains an integrated app usage statistics system. It tracks which app is used when and how long.
The data collected by this system can be accessed by every app with the correct permissions - therefore you can find a lot of apps that are able to display the app usage of your device.
Based on this information you can easily find out which app(s) you have not used for a certain period of time.


text:
Mobile internet doesn't work on browsers with VPN turned off, but it works in some apps, and works via Wi-Fi in all apps
I cannot use any browser with VPN turned off using mobile internet, but I can use other apps, such as BBC or Viber. I also can access the internet via Wi-Fi with VPN turned off. I have resetted APN settings many times, but it will not work. I cannot turned off proxy because there is no such an option. The proxy section is blank. When I fill in the blank with some random letters, and then blank it again, the internet begins to work, and after a few searches on the browser stops. Actually, when I change some other sections of APN the internet starts working, but then stops. Tell me please what is wrong. I am clueless about whether or not the problem is with the tablet or the mobile data provider. Because when I put a SIM card from a different provider into my tablet, it worked. And when I put my SIM card into another device, it also worked in that device. I called the company for help. They say that my APN settings was out of order. They sent me new ones. That also didn't solve the problem I have even resetted the tablet to factory settings. To my chagrin, it hasn't worked.

Make sure proxy is turned off in mobile data settings (APN), could be the culprit here, some proxy may be configured to work on specific sites or apps but on on some, alternatively reset APN settings

You are right. It has to do with proxy, but I cannot turn it off; there is no such an option. I can just fill in some data in the proxy section. It is blank.  What I did is I entered some random letters, and then blank it again. It worked, but it worked only for a few minutes. Then it stoped.

It worked a few times I repeated that, and now it doesn't work even if I fill in the blank and clear it.

And by the way I had not had such broblem before on the device I use.

Try resetting APN setting to default, Settings>MObile Network>Access Point names> Reset to default

I have done many times, and it doesn't work

Navigate to settings>system>reset options
click on "Reset Wi_fi, mobile & bluetooth.
This will however reset your your phone network settings
I had experienced a similar situation and this was the only solution that worked for me.
Did this work for you?

It have resetted it; nfortunatly, it hasn't worked


text:
Does installing, deleting and reinstalling an app make your phone slower?
I recently bought my oneplus 7 pro and I was wondering if installing a certain app, deleting it, and reinstalling it again makes my phone slower. I was forced to do this to a certain application today.

Reinstalling an app is no different than installing a new app. App performance is a function of the device's hardware (ageing affects performance because of new apps developed for better hardware in mind) and code optimization AFAIK. None of this seems to be the case with your app and the device so it should not affect the performance.

The only possible way I see to make your phone slower by re-installing an app would be that the flash memory degrades a very tiny bit - but that is pure theory. In reality before that effect would be recognizable to you, you would have to re-install an 100MB app a thousand times every day for may be a year or more.


text:
Phone no. display on Android pie?
I am having Asus zenfone max pro M1,  now updated to android pie recently. Previousely the phone came with default  Oreo OS.
After checking the features of new OS , i have found out that the OS  has detected my phone no. and is also displaying it.  Before in  oreo OS it wasn't displayed or AFAIK it wasn't known to google.
My question is - isn't this is a privicy breach or google was already aware of it in oreo also , only  the no. was not  displayed?

There is a sub-permission under READ_PHONE_STATE permission that permits reading phone number. The new update probably has  a system app (most likely Settings app) which uses this permission.

@Firelord - Yes the number is displayed in settings app. :-)


text:
Multiple User Accounts on Galaxy S10/S10+/S10e
Samsung has disabled the Multiple User Accounts feature on the Galaxy S10.
How to set up multiple accounts? I mean the ability to create a separate Android home with their own app settings.
I want to be able to lend the phone to a kid or friend for a day without worrying about them messing with my files or banking accounts.

The clean way would be to install a custom ROM that supports multiple user accounts. Activating this feature using root may be possible however you don't know exactly what Samsung has removed and what not. Especially missing GUI elements regarding multiple user accounts can't just be enabled if they had been removed from the ROM.

I solved this problem on S10e using this guide.

Root your S10. That step is required for that procedure.

Install BuildProp Editor (or equivalent) and run it, grant it root permission

Touch the pen icon at the top

Scroll to the very bottom of the text file, and add the following two lines:
fw.max_users=3
fw.show_multiuserui=1

Touch "Save and exit"

Check that the lines are correct. No extra spaces, all characters written exactly as below:

Reboot

In Settings, search for "Users". You can now add new users:

The user addition UI is a bit buggy, screens randomly go forward/back. But just be patient, sometimes try a step again, and you should be able to get the new user created.
Note: People who really don't want to root their device for some reason can try this procedure to edit build.prop: https://beebom.com/how-edit-build-prop-without-root/

Do you know of an easy way to switch users?  Currently I need to go to the settings->accounts->users->user->switch which is lots of steps to just switch.  The icon isn't in the pulldown


text:
hard factory reset when partitions are messed up
I have a Google Nexus 7 (2012) which for no apparent reason entered an endless reboot loop. Trying to fix it with a fresh install of the OS via TWRP, I unintentionally messed up the partition table.
Now the device doesn't even show the Google startup screen. The screen stays bare dead whatever I try (power + volume down, up, upsidedown, usb plugged in, immersed in Coke, boiled...).
Is there a relatively inexpensive way to interact with an android device that has its partition table damaged?
(Of course, it is not detected by adb.)
details
Probably they don't add much to the description of the problem, but for the sake of completeness, here are the latest steps of this tragedy.
Connected as root via adb I used parted to try and enlarge the size of the system partition (because the OS image didn't fit the system partition). It returned an error saying that it did not recognize the disk label.
/system/bin/sdparted # ./parted /dev/block/platform/sdhci-tegra.3/mmcblk0
GNU Parted 1.8.8.1.179-aef3
Using /dev/block/mmcblk0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
p
Error: /dev/block/mmcblk0: unrecognised disk label
(parted) quit
quit

So I reverted to fdisk, not really knowing what I was doing. It asked if I wanted to write a new label and it seemed a good idea to me to do so and I persisted the change. (In retrospective I see it wrote a DOS partition, which doesn't sound as good)
/system/bin/sdparted # fdisk -u /dev/block/mmcblk0
Device contains neither a valid DOS partition table, nor Sun, SGI, OSF or GPT disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that the previous content
won't be recoverable.

The number of cylinders for this disk is set to 481024.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): write
The partition table has been altered.
Calling ioctl() to re-read partition table
fdisk: WARNING: rereading partition table failed, kernel still uses old table: Device or resource busy

Then I switched back to parted, which had an apparently nicer output:
/system/bin/sdparted # ./parted /dev/block/platform/sdhci-tegra.3/mmcblk0
GNU Parted 1.8.8.1.179-aef3
Using /dev/block/mmcblk0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) p
p
Model: MMC HAG2e (sd/mmc)
Disk /dev/block/mmcblk0: 15.8GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start  End  Size  Type  File system  Flags

(parted) quit
quit
/system/bin/sdparted # exit

I rebooted and from that moment on the tablet shows no signs of life.

you probably don't read the disclaimer "Warning: Re-partitioning your Android may lead to a complete breakage of your device software and may render it unbootable!"

try to get it in bootloader mode with the proper key combo. try to flash from fastboot https://developers.google.com/android/images

Extending the partition seemed to be my only option, because for some reason the system partition was a few MB smaller than the (original!) image I was trying to reset to.

And it doesn't get to bootloader mode, the screen looks dead. And the usb port doesn't respond well. Even if the OEM driver is up to date, Windows 10 returns a device descriptor request failed error. Playing with partitions I may have messed up things at a rather  fundamental level...

maybe you can use the tegra-uboot-flasher to get bootloader mode back, but this is out of my knowledge and just speculation https://android.stackexchange.com/questions/212832/is-there-a-way-to-enable-usb-debugging-from-fastboot/212838#comment272476_212838

Thanks for the hint and sorry for the late reply. I had no idea that fastboot can connect in cases when adb can't. I spent these days trying to let it connect with fastboot but with no success, the tablet doesn't even enter in bootloader mode.

you need to flash/or exec U-Boot from tegrarcm via tegra-uboot-flasher-scripts

thanks, I thought a prerequisite was entering in bootloader mode (which I can't). However, even if was able to do so, I have a Windows host (not Linux), and on top of that tegra-uboot requires a few dependencies which makes it a bit harder. I might use a virtualized Linux but my (poor) understanding of the situation indicates that the essential problem is the inability to connect via usb in any way. The device doesn't respond to my pc driver's request. I was able to put the table in APX mode so its driver deviceid is USB\VID_0955&PID_7330, but I cannot find any official APX driver for Windows.

nope, you don't need bootloader mode. consider UNetbootin (bootable USB flash drive) https://unetbootin.github.io / here is a linux tutorial for nvflash: https://forum.xda-developers.com/showthread.php?t=1879228

ok, thanks. So no need for bootloader mode. I understand nvflash is not so straightforward. The XDA-developer's post you pointed at seems to fail in the end. Before flashing one need to have exported a few crucial files. I understand it is at the very least the BCT, a segment of code that enables the chipset to run the bootloader code. And I cannot find official Windows drivers for APX mode, which is the only way it promises to connect to my PC. (I'd rather not install unofficial drivers, for my PC's and tablet sake).

you can set up a sandbox PC if you are afraid about unofficial drivers, or Xubuntu 18.04 live distro (via UNetbootin, as i wrote)

Ok, I may use a "disposable" OS to help prevent malicious code from hacking my PC (and it is handy  the UNetbootin you suggested), but what about code potentially injected in the tablet by the driver? Also, I am rather surprised that Asus or NVidia do not offer any easy-to-use solution to factory reset the device (at a level lower than fastboot and adb). But I see it is my fault in the end, I entered an area of which I have no clue...

the default easy-to-use solution for factory reset is: complete bootable system image (read-only) = ROM / compared to a computer this is similar to BIOS. All apps and user content on userdata partition (wipe-able), similar to hard drive. You can expect the same support for bricked rooted phone, as you would expect for bricked mainboard with self-written BIOS. Thats why bootloader is locked

Maybe this will help you a little N7 Unbricking Information here the link to the links (scroll down)
https://forum.xda-developers.com/showpost.php?p=53554719&postcount=3

thanks, it turned up so complex... I feel I must me a firmware hacker to solve this.


text:
bricked mi a2 lite
Today I had a bad idea and decided to try to install Gcam on my A2 lite. So I installed ADB and Fastboot on my PC (linux), then flashed TWRP with the aim of later installing Magisk.
However, something went wrong: whenever I switch on the phone, the phone has consistently not booted to Android, but only to TWRP (which however was working). So I panicked and tried to fix this issue via fastboot, but things did not improve; in fact, they even got worse, as now the phone is unresponsive after TWRP's splash screen.
The only things I can still actively do are shutting the phone on or off, and starting fastboot instead of booting the system (which amounts to booting TWRP after all). Once connected the phone to my PC with a USB cable, ADB does not see the phone, but fastboot does.
I've tried a few things already, including flashing TWRP again and flashing a new system.img I've downloaded from the Xiaomi page, but with no success; Is there any chance to save my phone?
(I've tried to use a Linux porting of MiFlash, but with no success, either).

May i know how you tried to flash system.img

I got the file from the rom offered by Xiaomi.

but how did you flash it? did you use fastboot?

Yes, I did so. But with no effect, seemingly.

Did it report any error after your fastboot flash command?

To be hones, I can't remember. But I've to do it once again, right now, and the outcome is:
...
FAILED (remote: unknown command)
finished. total time: 0.020s

please try running fastboot reboot

Let us continue this discussion in chat.

@helper so finally it was your solution: "did you get your system.img from here: http://en.miui.com/download-354.html"

Good it worked.

Get the system.img from here: http://en.miui.com/getrom-354.html  and flash it


text:
Packet capture on Android x86, any ideas?
how can I run packet capture on my virtual machine (VMware-android 4.3)?
tried more and more to do, facing the same run-time error :
"Unfortunately, packet capture has stopped".
just to note that my host machine internet connection is based on Mobile USB tethering by PdaNet application.

The most reputable software I am aware of would be WireShark.  The software is open-source and they have detailed documentation on their wiki and docs page, as well as free online tools.  For the full list of downloads available -- including 3rd party builds -- go to this download page instead of the default one.

I specifically prefer packet capture because it has own decryptor with HTTPS protocols, so you don't need any skills to do this like WireShark.


text:
Device does not boot
I have a OnePlus 6T i disabled my magisk hide and rebooted but it gets stuck in the animation of a red dot and two white dots revolving around it after sometime it boots in twrp.
i have uninstall.zip for magisk but the names on my sdcard are weird and when i try just putting the magisk uninstall via mtp among the crypted files using my pc it says "this device has either stopped working or been disconnected"
sideloading modules says magisk not installed
thanks

You could also wipe data via TWRP.
This had happened to me as well, just select reboot in TWRP, then change current slot to a and then click system.

I have already done this and it has worked. thanks


text:
Message Pop up, how to disable it
I am new to Android with a Samsung A70 ( I really like it) but struggling with one element.
Can I stop pop up of WhatsApp and Messages coming on to the phone but still get a notification of the message on my FitBit?
Its just when the phone is sat there anyone can see the message if its not on Locked Screen


text:
Where to get old LineageOS ROMs?
I have a few old devices which I want to put on LineageOS. This time it's about a Samsung Galaxy S4 mini (GT-I9195, serranoltexx). But the official LineageOS website shows them as not supported anymore.
You basically are required to build the ROM for yourself, but this is beyond my knowledge and commitment.
I already have flashed successfully exactly such a device with LineageOS in the past, but do not have the ZIP around anymore.
Why does LineageOS not keep the latest versions of their ROM's around for download? Where to get a trustworthy copy?
Note: The same happened with cyanogenmod earlier. The did not store older ROM's too.
Note2: These devices were still on sale on recycling shops recently.

To answer the question (getting old builds) directly - there are people who foresaw the need and stashed some of the builds elsewhere: 1, 2.
As for the reason to it, it's right in their FAQ. The main reason would be to save bandwidth/storage, since the project is a non-profit.

Thanks for this insightful answer. I choose this one over the first, because it also addresses the why.

It's sad, but understandable, that they deprecate old builds. In face, I only try alternative ROM's on older phones I plan to recycle for my family use.

Using unofficial builds on XDA isn't necessarily a bad choice - in fact I myself am an advocate of doing so. The Android version / security patch will be more updated, and most devs are trusted and communicate with users through the forum freely. If there's a relatively bugless unofficial build for your device, I say use that instead. As you can see my answer is more to directly answer your original question :)

Removing old builds for saving space is reasonable but at least they should have recorded the SHA256 hashes on the removed builds to make it possible for people to search for them.

You can try XDA-Developers to download Lineage OS for your device. But the ROMs posted are not official versions and might not always work as smoothly as the official. The version posted on the link is Lineage OS 16.

Thanks. They seem to have even recent builds. I'll try them out tonight!

Although I was eventually not able to flash (because of internal storage failure on the phone) these ROM's seem to be the ones I was looking for.


text:
Mi 9 (M1902F1G) running MIUI 10.2.15.0 issue with fitness trackers
I'm seeing issues with my new phone that it's not keeping the GPS enabled when fitness trackers are running.
E.g. a bike ride consists of a straight line between the start and end location.
I've tried Ghostracer and Strava and both seems to be having the same issues.
I've tried switching the "Battery Saver" setting for both apps to "No restrictions" (they were both previously on "Battery saver (recommended)"), but that makes no difference.
Anyone else with the same issue or ideally a fix?

Problem seems to be with the "Use Adaptive Battery" feature.
I'd guess it's not clever enough to differentiate between an app not being used very often, and an app being used after being recently installed.