text:
What could cause a page opened on Firefox to have an enormous data usage?
I have opened the rather innocuous page on reputable website Quanta Magazine using Firefox Android 65.0.1 (with NoScript installed) and left it open.
The data usage rapidly burned through 1 GB of data transfer via the mobile network, which is more than I use in a month in general.
I closed the page, stopping data usage. Reopened it, and on it went. It has blown my data usage for the month out of the water.
The graph from "Settings > Connections > Data Usage > Mobile Data Usage" is eloquent:

I have pumped the URL through Sucuri just to make sure whether there is a known evil in that page but it comes up blank.
What could be going on, and do I find out?

It's definitely something from d2r55xnwy6nx47.cloudfront.net - There is bunch of stuff from that cache being hovered in. When I block that URL in NoScript, there is scant data transfer. Set it to trusted and boom - you can literally hear money going to the mobile operator.

Unprotected Chrome has no problem with the page. Downloads about 10 MiB (the embedded images and the video?) but after that no particular activity.

At home, checked what Firefox Desktop does: It behaves as expect, once the page has been downloaded, it stays downloaded. Firefox Mobile, connected to the WLAN, has another approach: it continuously bursts 30 Mbps downloads over the DSL once d2r55xnwy6nx47.cloudfront.net has been whitelisted in NoScript.

You have a valid problem. https://i.stack.imgur.com/BPm7e.png

This is unrelated to No Script because my test was conducted without it. Yes, it would be best if you show your findings or at least my linked image as a proof of a bug when filing it with Mozilla.

https://bugzilla.mozilla.org/show_bug.cgi?id=1531380

Do you know what embedded miners are?
https://platform.jsecoin.com/?register=1&utm_source=referral&utm_campaign=aff139531&utm_content
http://join-shortest.com/ref/bdb9481b4c?user-type=new
They are a way for a webmaster to make money off of their webpage without a bunch if banners. The visitors of the website are having some if their computer power used to mine cryptocurrency. That uses data, right?

Absolutely. I do hope that Quanta Mag knows to not get its web pages hijacked though. Plus note: It's just traffic, no CPU usage. I suppose it's some bad interaction between Firefox and the page, but I would need tcpdump to be ready for a debug session.

Miners would more affect the CPU usage, not the data usage.


text:
Why doesn't BOINC use the CPU power fully on my Huawei P9 lite?
I installed BOINC on my Huawei P9 lite.

model VNS-L31
build VNS-L31C432B414
Android 7.0 (stock)
CPU Kirin 650
RAM 3 GiB

I want the phone to run BOINC applications, when fully charged and connected to a wall outlet or PC. However it seems, that BOINC has no means to acquire all computing resources on that device. Antutu Benchmark shows no more than 68% CPU load and when inspecting the actual CPU load only four of the 8 cores are showing full CPU load the others exhibit half load and lower CPU clocking.
Battery temperature doesn't exceed 29°C, which is fairly low. (I'm not living in Siberia)
Computing performance seems to be low, too, when compared to an old Samsung Galaxy S5 with lineageOS installed. I tried to find all settings concerning power usage and so on, but there are virtually none execept power saving mode and ultra power saving mode.
When I start the stress test of AnTuTu Benchmark, the battery temperature rises to 37°C, soon. All cores show nearly full load then.
Now what bugs me is:

Is the CPU usage for background processes limited by some means?
Is it possible that BOINC applications are so inefficiently programmed, that they can't acquire enough computing resources to create full CPU load?
Can this be circumvented by rooting the phone and/or installing third party apps / non-stock ROM?

Don't get me wrong, I don't want to wear down my phone intentionally (in fact, on my old phones I don't give a s*** on that). But I want to have control over what I do on my devices.
Update
Did a test run with CPU-Z. It clearly shows, that the overall CPU-load is just 30% while Boinc running in the background. So the device must be throttled somehow.

** Update **
I added the thermal measurements from CPU-Z.
[
It is rather obvious, that the temperatures can't be the cause for the throttled CPU. Anyone more clues why and how BOINC is kept from using the resources and how I can influence that behaviour?

Yes it is true, the Huawei P9 lite has a Octa core CPU, however not all 8 cores are the same. Instead it follows the ARM BIG-little concept:
The 4 "BIG" cores (2.0GHz) are dedicated for maximum CPU speed. They are optimized for maximum performance (at cost of power consumption).
The 4 "little" cores (1.7GHz) are optimized for minimum power consumption. They are pretty slow compared to the BIG cpu cores (more than the 15% the cpu speed comparison indicates) as they are mostly used when the phone is in stand-by mode and does not have to compute much.
Therefore it is not unusual that only 4 of 8 cores are used. You should use a system info app that displays the current (not the maximum) CPU clock speed of all 8 cores. You should see that 4 cores work at 2.0 GHz - so the BIG cores are used.
For my device the app CPU-Z works and displays the clock speed (the refresh speed is not very high so you have to wait some seconds).

Hello, did a test run with CPU-Z, showing that even the strong cores are throttled.

@Ariser Throttling is a different thing, likely caused by thermal restrictions.

@AndyYan I don't think it is a thermal issue, because all temperatures are around 30°C +-3° according to CPU-Z. If thermal throttling was active in this region, the device would be unusable in a lot of regions around the globe.

source: Stack Exchange

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

sort: votes


text:
Cannot reach fastboot from Recovery Mode
Beforehand: Sorry for asking. I was sure this wasn't duplicate.
I have made myself a soft brick. The story: used kingoroot or something similar, then was too much in a rush hitting the "yes, please, ruin my rooted device via a firmware update!" button.
Now I made it to this exact situation:

I can reach recovery mode
I get the right answer when testing for root in recmode
I think I got the right rom file but it wont install correctly neither from adb sideload nor via applying it from external sdcard

My guessed salvation: updating the bootloader because I think this gives me the problems with sideloading. I'm here to ask if this is correct and if so how one does so.
EDIT:
Apparently I made some mistakes. The rom archive lists some roms that are neither tagged by OTA nor by a build number (I think I have to choose one of those because None of the ones that have a build number have the one I need). I need build number B116 because it says so an the recovery screen. I choose this one because I am a native german speaker. Is this the correct file?
I unpacked the file and found a file named update.zip containig something that looked like a system. I tried to sideload it and I tried to apply it from sdcard both didn't work.
EDIT:
Whenever I try to sideload the rom sideload gets stuck at 52%. Trying to install it via sdcard results in abort.
EDIT:
The most successful way seems to be installing from sdcard which I reread how to do here. I forgot to put the package into a directory called dload. When doing this installation does not abort in a split second but rather a few seconds later saying can't install this package (2016 02 27  17:38:09 CST over newer build (Thu May 4 14:58:09 CST 2017) shame is, that the newest non-OTA builds are all older than the given date.

ADB and fastboot are different. Former is accessible when in ROM or (custom) recovery, later is accessible only in bootloader mode. There could be more than one bootloader modes on a device, one is fastboot. So, fastboot won't be available in recovery. Flashable zips for recovery and fastboot are different; one can't be flashed in other mode. Now what's your question?

question: why doesn't flashing work and what can be done to make it work

The file you linked is an OTA file i.e. it's just an update, not the complete OS for your phone. It can be applied only to a working ROM. If you want to flash complete ROM, find the stock ROM flashable file for your device. Or flash factory firmware using flasher software from PC. If you have an unlocked bootloader, you can also go for custom recovery and custom ROM (provided that those are developed for your phone).

ok, didn't know about what OTA means either, thanks again. I'll try to find the right image and flash it via sideload if that works.

Found all roms. I need Y360-U61V100R001C577B116. Unfortunately for B116 there are no full roms only OTA roms. Can I use one from a different build? I tried but I got * failed to write data 'protocol fault (couldn't read status): Success' *  from linux after sideloading.

Is this phone a Mediatek (MTK) device? If so, you can flash it using SP Flashtool, that's the easiest way to do. You can't reach fastboot from recovery, although some devices have options to reboot into bootloader mode from the recovery. There should be key combo to boot into bootloader, just look around the internet

Check the following link: https://forum.xda-developers.com/android/general/guide-huawei-y360-u61-stock-rom-factory-t3775937/page1

@esQmo I don't have access to a PC. I understand that given that sideload wont work for me even that I have the right rom (which is a question that I'm still unsure about) using a different flashing software would be the way to go. Is there software for linux that is expected to work better than adb?

Maybe this works using wine

or one just tries this out

doesn't work due to dependency problems that couldnt be resolved

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


text:
How to limit car speed with a ELM327 converter?
There are plenty third party devices which allows to never go faster than speed limits.
But when having already a ELM327 ᴏʙᴅ2 converter, why not using it directly through an android tablet instead of purschasing a separate device ?

Because it isn't designed for Android?

@SiXandSeven8ths it can work with android but this is just the converter hardware. It’s like a bluetooth to ᴜꜱʙ cable : without software it does nothing. And I don’t only to collect data but to write and act on commands.

Sounds more like a developer/programming topic which is off-topic.

@SiXandSeven8ths if there is an app which already exists, then no.

Revise your question then, because that's not exactly what you're asking.

@SiXandSeven8ths or you can suggest an edit because it's clear that I don't want a programming answer as per currently written.


text:
How to safely root the Samsung Galaxy Tab A 2017 (SM-T380)?
I am wondering what would be a safe way to root my Samsung Galaxy Tab A 2017 (SM-T380)?
I understand there is CF-AutoRoot and such but I have no experience in rooting any device with that method and I'm extremely scared that if I attempt to root my tablet with CF-AutoRoot and such that my device will get bricked.
Details about the tablet below.
• Android Version: 7.1.1
• Security Patch Level: January 1, 2018
• Build Number: NMF26X.T380DXU1ARB3
• "OEM Unlock" option available ✔
I also have another question. The tablet has a pending update to Android Oreo, if I were to update the tablet and the tablet was rooted at the time I updated it would it affect my root?

I removed my RMM prenormal with miracle box no box and after finding the twrp tar on xda used it to install a custom zip file i made with superr kitchen and a rom from samfirm .
There are no roms a


text:
Termux:Widget and Emacs: can't start subprocesses
I have some tasks that I like to do using Emacs on several different operating systems.
I have been using Termux so that I can access these tasks on my Android phone.
To reduce setting-up typing in the file-editing part of this workflow, I've installed Termux:Widget and written a two-line widget script that does
filename=$(a little shell logic)
emacs $filename

So now my phone has a button on the home screen that I can push and it opens up the file that I want in the editor.  That part all works fine.
Frequently, once I've started editing, it's convenient to run a shell script.  It's nice to be able to run the shell script in an Emacs buffer so that I can use the regular buffer-switching commands to interact with it.  If I open a fresh Termux session and type emacs at the prompt, then I can do M-x async-shell-command, use relative filenames and tab completion to find the name of the script that I want (e.g. ../my-script.sh), and execute it from within Emacs.  That part works fine.
However, if I've started Emacs from Termux:Widget, Emacs is unable to spawn subprocesses.  I get errors like
/data/data/com.termux/files/usr/bin/sh:  1: ../my-script.sh: not found
/data/data/com.termux/files/usr/bin/sh:  1: /data/data/com.termux/files/home/whatever/my-script.sh: not found

I believe the relative and absolute path names are correct because I am using tab-completion to check them before asking to execute.
This seems like the kind of problem that termux-exec was invented to fix.  However, it isn't working by magic, and I'm finding myself confused by the documentation.

I solved this while I was trying to be thorough while writing the question: it was in the documentation, I just couldn't figure it out.
I needed to set LD_PRELOAD, as documented by termux-exec, so that Emacs runs with the modified version of the exec() system call.  My two-line script is now
PREFIX=/data/data/com.termux/files/usr
TERMUX_EXEC=${PREFIX}/lib/libtermux-exec.so
[ -e $TERMUX_EXEC ] && export LD_PRELOAD=$TERMUX_EXEC
filename=$(a little shell logic)
emacs $filename

The extra existence-checking cruft is so that LD_PRELOAD remains unset (or unmodified) where I run this same convenient script on my non-Termux systems.


text:
I can't turn off "Easy Mode" on Galaxy On5 and there are missing options in the "Settings" Menu
I really need help here. I accidentally turned on my sister's "Ultra Power Save Mode" and, when I had realized I had done this, I turned it off. When the phone rebooted on again, it asked me what kind of set up I wanted, and me not knowing what it was talking about, selected one of the options and now it's stuck on "Easy Mode", but the apps are limited and there are missing options from the "SETTINGS" menu. I'm at my wits end and I'm afraid I might have to buy her a new phone. If anyone could answer me, that'd be amazingly helpful...

From Samsung Galaxy S5: How to Disable Easy Mode in Android 4.4.2 Kitkat:

Method #1: From the notifications panel

Swipe down the top of the screen to open up the notifications panel.
Tap the gear(1) to go to the easy settings menu.
In Easy settings, tap Easy mode .
Tap Standard mode to select it.
Tap Done button.

The easy mode will be disabled and the standard mode will be applied in your phone.

(1) Added emphasises due to original article has a picture instead of text.

Method #2:
From the Easy settings shortcut in Home screen
  By default, you can find the easy settings in the Home screen in easy mode as an app and you can use it to access the easy settings menu to disable easy mode. See the following steps to disable easy mode:
  From the main Home screen, swipe the screen from right to the left until you see the Easy settings shortcut/icon  and then tap it to go to the easy settings menu.

Tap Easy mode .
Tap Standard mode to select it.
Tap Done button.
  The easy mode will be disabled and the standard mode will be applied in your phone.

If in the easy mode you'll be provided with a simpler layout and the easy settings menu, then in the standard mode you'll be provided with a conventional layout and more complex settings menu. Also, in the standard mode, you can find and use all features owned by this phone unless you disable them.


text:
Encryption Unsuccessful even after system backup restore
The steps I performed:

Flashed TWRP with Odin
Made backup
Flashed LineageOS 14.1 with TWRP
Flashed SuperSU with TWRP
Flashed Open GApps with TWRP
There was a problem, Google Play Services kept crashing, I decided to restore stock ROM
Restored the backup I made in 2 with TWRP
Opened my restored system and decided to encrypt the device
Either the encryption failed itself or I somehow disturbed it
After restart Encryption Unsuccessful keeps appearing
I restored backup from 2 again I still get Encryption Unsuccessful
I flashed LineageOS again - started nicely
Once again I restored backup from 2 again I still get Encryption Unsuccessful

In the meantime I wiped Cache, Dalvik Cache, Data and System numerous times.
So it looks like the stock ROM keeps seeing the information about the failed encryption process even though I wiped the 4 partitions mentioned above. Interesting part is that LineageOS doesn't care.
Any ideas on how to get the stock ROM back on its feet?
EDIT
Flashing the stock rom with Odin didn't help either

What type of backup did you made (how did you do the backup)?

@Robert via TWRP "backup" function

Found out the way to fix it:

Download stock firmware (*.tar.md5)
Flash it with Odin (it removes TWRP and replaces it with a standard recovery)
Start Android - still "Unsuccessful encryption" error
Boot into recovery mode (now it's standard recovery instead of TWRP)
Run factory reset
Start Android - now it finally starts - problem solved
Flash again TWRP with Odin
Restore the old good backup with TWRP
Done

So basically the factory reset form the original recovery mode fixes it.
Also I found out why the tablet bricked. When it performs encryption process it looks like it's off (no lights, sounds or anything). Do not disturb it, after 20-30 minutes it finishes the encryption and turns itself on. Just leave it be until the screen turns on.


text:
Google Assistant News are being emailed to me in the wrong language - how to fix?
I'm traveling and my Android phone's Google Assistant is now set to understand two languages, which is fine.
What's not fine: Google suddenly decided to email me all the info in the second language which is not English.
The emails are coming from the assistant-noreply@google.com address, so there's no way I can just reply and ask them...
I don't mind the emails, but I want them to be in English. Yet, they are coming exclusively in the second language. Drives me nuts. How do I fix this situation?


text:
Disable Airdroid keyboard by default
My problem is that whenever I connect to my Android 7 phone via Airdroid Mirror on Windows 10 the Airdroid keyboard gets activated. Of course I can deactivate the keyboard by clicking the keyboard button on the function bar but this is annoying. I don't want to do this every time.
How can the Airdroid keyboard be disabled by default?

Do you see any related entry under Settings -> Language and Input -> Keyboards?

@Firelord Unfortunately not. What shall I do?


text:
How to disable EdgeEffect when over-scrolling?
When you have only one home screen or scroll past the start or end of multiple  home screens, EdgeEffect appears, as shown on the left in the image. Can this be disabled?

It is called EdgeEffect.

Thanks , I searched and searched and never found that name


text:
Need to recover data from SD card as used Android Internal storage from PC
I had an SD card as internal storage in my Android, reset my phone to factory. SD card would no work in that device. I am no longer able to use that device because the screen is smashed anyhow. How can I recover the data from the SD card? I tried to reformat on my laptop but the disk is write protected.

Using SD card as internal storage is risky. Because, if anything happens to SD card or if factory reset device the data on sd card is not further usable. I had experienced this: I have moved some app data to sd card previously, when SD card is removed, those apps are grayed out and cannot use them.

AFAIK using sd card as internal storage will do some encryption on sd card. so that you cannot use that sd card on another device without erasing data. Also, the same may happen if you connect with a pc.

Is there anything I can do to recover it from my PC, without access to the phone is was encrypted on? Nor the key to the encryption?

This is very device dependent.
The first option you should try when recovering your data from the external SD Card is to REMOVE the card, Place it into an adapter & put it into a computer.
Try to access the data that way,
From my personal experience a research on Android, I can not find any reference to the SD Card being encrypted as the comments suggest in your question.
Samsung device's do have SD Card encryption by default, However this is not say an " Android " thing to be expected, usually you need to manually encrypt your SD Card.
The SD Card is however Formatted in Fat32 or just Fat, and it usually has a Linux partition for speeding up transfers.
You need to place the card into a computer and use a data recovery software... Because I'm on Windows 10, I suggest Recuva by Piriform because it has a decent home version.
Another option to try if you do have encrypted data is to do a recovery anyway.. Often not all data is encrypted, only necessary data to read the drive is encrypted.


text:
Running metasploit on android error
I am trying to run metasploit on Android using Termux.
I've already installed it but when i try to run msfconsole command i get this error:
ruby: No such file or directory -- /data/data/com.termux/files/home/metasploit-framework/msfconsole (LoadError)

Thanks for response
EDIT :

Second EDIT

Please Share a Screenshot of the Home Directory on your Termux Terminal....to do so... Simply Execute the following commands and Share the Screenshot of the result... cd ~ && ls

You should try to execute metasploit and then make the screenshot. How did you install metaspoit?

I installed it from this tutorial : https://null-byte.wonderhowto.com/forum/to-install-metasploit-framework-android-part-1-termux-0186792/            Second screenshot added

If you're new to MetaSploit Framework, I strongly recomment against trying to run it on Android. MSF itself is meant for experts, and configuring it on non-GNU/Linux systems add another layer of complexity as well as requirement for previous knowledge in related subjects.

Also, the tutorial provided many ways of installation. Which one exactly did you follow?

I followed the first way.


text:
My phone stopped detecting custom notification sounds (but custom ringtone sounds still work)
I installed some custom notifications sounds on my BLU Advance 5.5 running Android 6.0 a few months ago and they've worked fine for a really long time until when recently all my notification sounds went back to default, so I try to change back to any of the old custom sounds that I'd been using, but they won't show up in the options. My custom ringtone sounds didn't change and still work fine, but my notification sounds just won't show up.
I've tried rebooting, renaming, changing the location of the file(s), and clearing the cache, but nothing works.
I don't know what to do anymore.

The fix for me was to rename the custom sound files (the .mp3s) and make sure they started with Capital letters. Seems crazy I know, but the one thing I noticed that was different about my custom files and the stock ones was that mine weren't capitalized. As soon as I changed that, they all showed up and I was able to select them. My phone is a Samsung Galaxy A51.

Any sound files stored in a folder named
Notifications

will be found by the system and displayed as an option for a Notification sound
Any sound files stored in a folder named
Ringtones

will be found by the system and displayed as an option for a Ringtone sound
Note that it doesn't matter where in the system your Notifications or Ringtones folders are stored, Android will still find them. Notifications in /media/notifications will be found, and so will sound files in /Music/Notifications. You can also have more than one Notifications or Ringtones folders.


text:
Apps whitelisted in AFWall+ without my knowledge
I've installed a firewall (AFWall+) on my phone, and I've manually whitelisted every app I wanted to allow accessing the Internet, including system apps. So everything is blocked by default, and I add apps to the whitelist as necessary until what I need works and nothing beyond that.
I've just discovered some apps in the whitelist that I never whitelisted myself and don't even remember ever seeing before to be honest. These are:

"Intent Filter Verification Service"
"Market Feedback Agent"
"Print Service Recommendation Service"
"Google Partner Set Up"

From what I can see, these are from Google, although I'm not clear on what they do (except the Feedback Agent).
How could this happen?

System details:

Device: Samsung Galaxy S5 Duos (SM-G900FD)
OS: LineageOS 14.1
Android version: 7.1.2
The phone is rooted with SuperSU.

Guess you didn't read this explanation by developer regarding system apps. You need to consciously blacklist them if you want, by default they are white listed.

Google Partner Setup

No one seems to know what this does and what data it transmits/receives
  Rec: Block

Market Feedback agent

If blocked, cannot use Google to submit feedback to app developers when apps crashes.
  Rec: Block if not using the Google Play store, otherwise allow for all connection types except LAN

Other two are not covered in this list so you could ask developer on his XDA thread. If you aren't using Print services, it should be safe to disable IMO

You've guessed correctly, I hadn't read that. However, AFWall+ doesn't have a concept of blacklisting separately from a whitelist. As I've mentioned in the post, I disabled everything, and I've been enabling  ("whitelisting") manually whatever was necessary. I never enabled those apps, yet I found them enabled. The question is: how could this happen?

It's been a long time since I used this app so it's possible I am mixing up white/black list. Yet, these being system apps are by default enabled as explained  by developer. You need to disable them based on your need and suitability.


text:
Forgot Password
I can´t remember my Samsung Galaxy J7´s phone password and I have to reset it. But I don't want to lose all of my pictures and etc. How can I still have all of that stuff without downloading it or getting on my phone?

•Note this is an advance task
 •This is created by me and I've tested this many times

First of all if you have enabled oem unlocking you must have heard custom recovery and twrp is one of them.
Install a twrp using Odin you can go here Samsung j7 pro or Samsung j700t here. If you're phone model is not in the list then tell me your phone model or just search on your own.
After installing twrp power off your phone then press volume up + power ** + **Home button together then you will be booted to twrp to delete your passcode goto advance > file manager then navigate to /data/system/ and delete all .key files and also locksettings.db after doing those just reboot to system then the passcode/pattern/pin is gone

You need to have your stock boot where its stored on your stock firmware download your stock firmware from here or here. After that extract the firmware, you should get something like AP, PDA, CSC open the AP using winrar or other archive tools if there's no AP then open PDA find boot.img then extract it. After getting your stock boot you need to download assayyed kitchen here. After download extract it to some folder then open assayyed kitchen.exe after that it should create work folders, put your stock boot on the work folder then goto assayyed kitchen then type 12 then 1 to unpackimg after that you need to type the number of the -enable USB debugging by default (I forgot the number) then after that recompile the boot press 2 and enter .
Copy your moddedboot then create an archive to it using any archive tools archive it as an .tar file after that copy he boot.img.tar to the desktop then power off your phone after powering off hold volume down + Power button + Home button together then your phone will be booted to download mode after that open Odin choose PDA/ap choose the stockmoddedboot.img.tar then click flash after that connect your phone to the computer then the flashing process will continue.
After installing the stockmoddedboot power on your phone then connect the phone to PC then type  adb devices, there would be a information that will pop up to your phone just click grant/accept then type adb shell rm /data/system/gesture.key then adb reboot
Your phone would be booted without a passcode/pattern/pin

P.S. if anyone try removing there frp you can use the method 2 but you need to download some software to remove frp using adb and fastboot

There are a couple of ways to do so...

First, if your phone has a Google account logged in go to Android Device Manager's Website and Login with your Google Account...You'll find an option to change the device's lock code along with several other options....IF this fails...as sometimes Google denies you the privilege to change the passcode in case your Google account shower suspicious activity by saying that the phone is already protected ....go to method 2
IF YOU HAD A SAMSUNG account logged in on the phone go to Find my Device and Log into the account which was on the phone...this will Surely work and get you an Option to Change your phone's Password/Pattern


text:
How to control Android based tablet from Windows or iMac desktop?
I have a setup in office where on a desk is fixed samsung galaxy tablet on a stand. On the same desk I have Windows PC or iMac. Customer is looking at the tablet. I am the desktop user and I want to control tablet from my desktop to demo a website. Customer looking at tablet should not see any part of my desktop other than the website. Since the stand secures the ipad and hides home button on ipad, I want to be able to access the home button from my desktop to wake up ipad from sleeping.
What is the solution for above?

Team viewer has a remote access program that can be hosted on Android.
This guide has a free solution but I haven't tried it and I don't know if it'll unlock the device (it does specifically say it can do the home button).


text:
Upgrade Android to a new major version in Virtual Box
Is it possible to upgrade an Android OS in Virtual Box to the next major version?
I've installed Android v7.1, but want to upgrade to v9.
I've been unable to find an ISO for v9, so I wonder if there is an internal upgrade process I can use.

Are you referring to an VM image with Android-x86 installed?

Yes, @Robert one with v9. I wonder if I am able to upgrade natively to the next version?

You don't find an Android x86 9.0 image because now (2019-03-03) they are still working to get the Android 8.1 release finished.
As far as I know the Android x86 project does not provide the possibility to upgrade an existing installation. The recommended way to get a new version whilst keeping the existing app data is to use two partitions, one system partition and one data partition.
Therefore an "upgrade" can be done by creating a new virtual machine, with an empty system partition and the existing data partition for the old installation:
https://groups.google.com/forum/#!topic/android-x86/5XrE2lo7uac


text:
Change layout of Gboard (space between letters)
I have installed Gboard on my Android 7 device. My keyboard looks now like following:

Is it possible to change the layout in something like the following? I mean the gaps between the characters, i.e. each letter should be in its own box.

If your device is rooted, you have a Magisk module for Gboard that offers plenty of alternatives

You can change to another theme/layout in the settings.
Here's a how-to guide.
If you want to build a completely custom keyboard that's more work but also possible.


text:
Does the Pixel 3 need an active or passive USB C to 3.5mm Adapter?
Does the Google Pixel 3 Phone require an active or passive USB C to 3.5mm jack adapter?

Google store doesn't sell this adapter in India but links to retailers whose product description shows it has a DAC chip and therefore  is active similar to this. Note that this works on Pixel 2 and Google Support for Pixel 2 clearly mentions it has a DAC and  is active.

Pixel 3 connector specs are not made available by Google AFAIK

I got a chance to try it and the passive one doesn't work on the pixel 3. Annoying that they don't say anything anywhere.

And even when they say... It maybe wrong https://android.stackexchange.com/q/159694/131553


text:
Mirror Android Tablet to VGA monitor via Cable- NO DiSPLAY
Specs:  Samsung Monitor S222B300B,
        Samsung GalaxyTab 2 (micro usb slot),
        Monitor cable,
        Male micro usb to Female HDMI w/usb power slot,
        Male HDMI to Female VGA port
notes: all connections has been connected, power was switched on the monitor, power on the male micro usb to female hdmi cable was plugged, monitor tested with laptop to display screen and working fine
problem: monitor does not mirror tablet's screen which should easily be detected but it does not.
question: i bought the 2 sets of conectoon cables thinking there might be a defect 2nd one - same thing. does my monitor have a problem or does all monitors works for this kind of set up? is there anyhting that i should have done to make it work?
hoping for someone's help. getting me crazy. iwanted to watch on a bigger screen dont like wireless options for the meantime.

If you have a computer hooked up to that monitor, and can hook up your phone via USB to the computer, I recommend Vysor. It's available as a chrome or windows app. Works great for screen mirroring, and the free version only uses USB
Note that there is a pro version of it, but basic functionality is free. You may also need USB debugging and ADB working


text:
Where does Android get these email addresses from?
In an app called Wirex an email autofill appeared. This is very confusing to me. The list contains very old emails, emails I had already forgotten 2 years ago.
I bought this phone in 2018. Where does Android grab these email suggestion from? These are all emails I created so no random email from contact lists.

I've had something similar happen to me before, though I do not recall the app that was doing this. But I scoured my google contacts and to try and figure it out to no avail.

Check what is the app's package name?

I found where they came from. I traced those emails to my google account. Basically they were stored as login information (chrome autofill)


text:
can't find mapping of "android.permission.INTERNET" permission to famous methods which should use it
I was trying to evaluate effective permissions usage of an apk using axplorer mapping files.
During evaluation I obtained an effective use of the android.permission.INTERNET permission equal to 0.
This sounds pretty weird considering that this is maybe the most USED permission of all (android doc just tells an apk must declare this permission "In order to perform network operation"...)
This weird result depends on the fact that in axplorer mapping files there aren't mappings of famous "internet using" methods (java.net.HttpURLConnection, java.net.HttpsUrlConnection, java.net.Socket etc...) with android.permission.INTERNET permission.
I also knew that axplorer project replaced pscout project, so I took a look at pscout's mapping files either and found that in pscout's mapping files of android versions from Jelly Bean to Froyo there actually ARE mappings of java.net.HttpURLConnection, java.net.Socket etc.. methods with the permission, but for 4.11-5.11 android version, there is no mapping with these methods, and the mapping files become very similar to axplorer mapping files of android more recent versions.
Someone can help me find out why I'm seeing this strange case in permissions mappings?
I need to evaluate permissions effectively usage, but a "zero usage" of android.permission.INTERNET has really to be false... Someone can help me with that? Maybe there's something wrong in my idea?

The readme states:

Maps are currently missing APIs with permissions checked in native code (Camera, etc.). We hope to provide these soon.

The permission android.permission.INTERNET is a permission that is mostly checked on native code level. Therefore you won't find much references to it in the API mapping files.
Update: The old mapping files that did include APIs for the Internet permission were as far as I know generated by manually reviewing the AOSP source code for permission checks. Over the time AOSP got larger and larger and the release frequency increased therefore this toot too much effort for providing those info for each and every Android release. Therefore the people who created the mapping files concentrated on the Java part which is much smaller and easier to check.

Thank you, that can be a point...
How you managed to know android.permission.INTERNET is only checked on native code level?

@Alessio I read it a long time ago. Additionally you can also derive it by logic: Android as Linux system allows to open socket connections using native Linux functions. Therefore if you want to enforce the Internet permission you have to implement the permission check also on native level. Once you have done that there is no need for additional checks on Java API level.

I did a check and actually it seems that THERE ARE some some mappings for the android.permission.INTERNET permission in axplorer mappingFiles... But these are NOT on the "famous 'internet using' " methods I mentioned... But on other java and method classes. The list of classes/methods follows:

com.android.providers.downloads.DownloadProvider
com.android.server.NsdService.getMessenger()
com.android.server.ConnectivityService.reportBadNetwork(android.net.Network)
com.android.server.ConnectivityService.reportInetCondition(int,int)
com.android.server.ConnectivityService.reportNetworkConnectivity(android.net.Network,boolean)

@Alessio That makes sense calls to services should be RPC calls to other processes, therefore before calling Internet relevant methods you have to check if the current app has the Internet permission. Otherwise you could (mis)use the service to do Internet related actions without having the Internet permission.

Sorry, I'm not getting it... Precisely what makes sense applying your reasoning and why? The presence of the mappings I showed in contents or the abscence of mappings for, f.e., java.net.HttpURLConnection?

@Alessio HttpUrlConection is a Java wrapper for the native Linux socket function. It is always executed in the current app process and therefore covered by the permission checks of the native Socket function. The external services are not part of the app and the app process. If you use a service that belongs to a different process (via RPC) your permissions no longer apply, instead the permissions of the app the service belongs to apply. E.g. the DownloaderService I assume is a system service and therefore has the Internet permission no matter by which app it is used.


text:
Default Alarm ringtone
Es file explorer can set the default ringtone for Alarms (this means that when you set a new alarm, xyz sound is already selected by default).  Factory "default" is set to silent.
Google Assistant will set alarms but uses the factory default sound which sisilent on my phone.
I do not like es file explorer.  Is there a way to manually do this without root just as es file explorer does without root?
Are there other programs that will do this with the system sounds.?
Btw, es file explorer will not do this with system sounds but only with my personal files.  Which is okay but not acceptable.

Mixplorer is very versatile minus the ES invasive payload

You can use Solid Xplorer. Alarms from Google also helps. Your alarm would have the same tone which was used in the last alarm. https://play.google.com/store/apps/details?id=com.google.android.deskclock&hl=en_US&referrer=utm_source%3Dgoogle%26utm_medium%3Dorganic%26utm_term%3Dalarm+app+oneplus&pcampaignid=APPU_1_BUx5XIG2JczkvAS1jIKoBw

thanks for the answers.  Mixplorer did not seem to have anything to do the job.

Honestly easiest way for me:

Download Zedge. (Free app)
Look up what sound you want (it has alot)
Set as "alarm sound"
It is now Google clock's alarm default

And it also has wallpapers,  ringtones,  notification sounds and so on. You can use them anywhere even Facebook messenger.
Hope this helps :)


text:
Does encrypting an Android phone also encrypt old, deleted files?
I'm going to be selling my phone soon. The advice seems to be to encrypt it then performs a Factory Reset. But does the whole internal memory get encrypted, or just the current, visible files? If so, surely that leaves old, deleted files recoverable.

That depends if a full disk encryption (FDE) or a file based encryption (FBE) is used. See https://android.stackexchange.com/questions/195713.

The problem is it's a 5.0 phone updated to 6.0. So I'm unsure. I'll be doing several 100% memory overwrites, along with Factory Resets and encryptions, just to be sure.

How do you do "100% memory overwrites"? Note that your device may have multiple partitions. Therefore you have to overwrite each of it that contains user data. Some partitions should not be overwritten as they don't contain user data and are required (e.g. on some Samsung devices there are partitions containing IMEI and other related stuff, without this partition the mobile network will not work.


text:
Prevent app from seeing installed apps
Is there any way, through settings or ADB, to prevent an app (that I installed) from knowing what other apps are installed?

AFAIK no. Not possible. One way is to use XprivacyLua Xposed module to activate this hook for that apo so that it doesn't see other apps

Also going with no as it might break Android. Android settings for example is an app, the launcher is an app, etc.

@CmosBattery ok it is a user installed app I don't want knowing what apps I have (nothing overly important either)

Android 13 Tiramisu (API Level 29) Will finally support this.
In the meantime I use multiple Android users or the Island / Knox apps.
Source: https://developer.android.com/reference/android/content/pm/PackageManager#getInstalledApplications(android.content.pm.PackageManager.ApplicationInfoFlags)


text:
How to prevent unwanted DBG_FMMDM spam from filling up your logcat buffers
I asked this question on Stack Overflow but was advised to ask it here.
I am attempting to debug an error using logcat in Android Studio on my testing device, a Galaxy s9 plus running Pie. Suddenly I have a really weird and annoying logcat output making it hard to view events:
2019-03-01 10:49:15.024 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:55][a] xdmGetAccountRegistration : true
2019-03-01 10:49:15.024 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:47][onDestroy] XDM ALERT REAMINED, SO RESTART DM SERVICE
2019-03-01 10:49:15.024 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:2][a] FMM Application Start !
2019-03-01 10:49:15.028 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:5][onCreate] XDM Service onCreate
2019-03-01 10:49:15.029 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:20][onCreate] Device ID is null!!, service not start !
2019-03-01 10:49:15.030 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:3][onStartCommand]
2019-03-01 10:49:15.030 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:2][onDestroy] onDestroy
2019-03-01 10:49:15.037 17645-17645/? I/DBG_FMMDM: [6.9.22][Line:30][a] Samsung Account Exist !!!
2019-03-01 10:49:15.038 17645-17645/? E/DBG_FMMDM: Warning!!! [6.9.22][Line:15][a] java.lang.NullPointerException: Attempt to read from field 'com.fmm.dm.b.a.x com.fmm.dm.b.a.ac.g' on a null object reference

This output runs over and over, to the point that my logcat is completely populated and there is no way to scroll up to see past outputs.
I'm sure it is some OS daemon, but I have never seen one that runs so frequently.
I have no idea what I/DBG_FMMDM is and why it is attempting to read from com.fmm.dm.b.a.x (whatever that is).
Has anyone seen this type of output before?
My testing device is a Galaxy s9 plus running Pie

Yes, I have seen this before. It is a security feature and it is coming from Samsungs Find My Mobile {FMM}(com.samsung.android.fmm). Samsungs version of Google's Find My Device.
It is located at:
Settings --> Lock screen (maybe Biometrics) and security --> Find My Mobile.
If the service is not wanted it can be deactivated.
I/DBG_FMMDM is short for Debug _ Find My Mobile Device Manager.
A breakdown of what log you posted states:
The FMM app is started but when it tries to get your Device ID it cannot find the IMEI for GSM and the MEID or ESN for CDMA phones so its returning null. However, when it checks to see if a Samsung account is connected to the device it returns positive.


text:
How do I set a custom SMS tone for a single contact in Android Messages running on Samsung Galaxy Note 8?
How do I set a custom SMS tone for a single contact? in the answer at https://android.stackexchange.com/a/16653/13886 it is claimed that this option exists in the dot-dot-dot menu, but it does not for my phone.

Was the feature there at some point, but then they took it out?
The phone is a Samsung Galaxy Note 8 running stock Android 8.0.0.
The Details button points to some central configuration that lacks adding a per-contact ring tone.
Is a specific app actually needed for this? Meaning, was this simply never built into Android? Or, is it there, but hidden by Samsung? Or  hopefully this is just user error, and I'm not finding the setting?

If you can't find it and everything leads to a dead end then yes it was probably removed. 3rd party app with the ability for custom sounds would be an alternative.


text:
How to merge different whatsapp chat histories stored in different devices
I have a few devices/sdcard with old whatsapp chat histories from the SAME account. How to recover and merge the old ones to the current one in the latest device?


text:
Cannot play .mp4 videos with the default video player
I downloaded some .mp4 videos on my PC and I want play them on my Samsung Galaxy Ace 2.
Despite the .mp4 videos can be played in my PC1 (with no problem), in my device (using the predefined video media player) the video cannot be played.
This screenshot shows the videos that my device cannot play them:

Only the video (pointed with the green arrow) - which is the default video that my device has can be played.
When I select any of the other videos, the device says: "Content not supported":

Each time I send the video (via cable from the PC to the device), it will show two options:
Do you wish convert (insert_video_name_here.mp4) before copy it to the device?

Yes, convert and copy (recommended).
No, just copy (File will copy, but it might be possible it cannot play in the device).

No matter which option I select, the video is not playable.
This is the information about the predefined app:

I was reading this answer and this one too about similar problems, but what I understand is due the resolution of the video, but I have no idea what can I do for play these videos in my device (despite those videos are .mp4 or .wmv files "the same as the predefined video - pointed with the green arrow in a previous screenshot").
I really don't want download another app and play the videos with them, hence I ask:
How can be played those videos wth the predefined app?

1 Windows 7 Professional 32 bits. Using Google Chrome "as video player" and the Windows Media Player.
PS: I also read about software which can convert videos for device-compatibility, but I'm not sure if those are free-malware applications.

What are the resolutions of the video not played and the one that the player was able to play?

@ReddyLutonadio resolution of non played video: width: 540, height: 960, playable video: width: 480, height: 320.

Are they using the same  audio and video codecs compare to the playing video? If not, try downloading a media converter for Windows, and convert the videos to use the same audio and video codecs than the playing one?

@ReddyLutonadio I don't know where to check if the videos are using the same codecs. I did tried convert to .mp4 and .wmv a single video using FormatFactory, but the same results ocurred: Content not supported (once tried to play in the device).

Download MediaInfo https://mediainfo.en.uptodown.com/windows, Use it to check the differences between the 'good' and 'bad' videos then change FormatFactory parameters based in them

@ReddyLutonadio thank you. After download MediaInfo, it seems that the differences was indeed, the codec. The playable video said: MPEG-4: 36.9 Mib meanwhile the other videos said MPEG-4: (Base Media): 2.26 MiB. Checking closely FormatFactory, there is a option called "all to mobile devices" - with different screen resolutions, and used it and it worked. Just a minor thing: when the device is vertical, the video is stretched, I have to test more, but, I can see them well in horizontal orientation. You can consider post your comment as answer and I'll upvote it. Thank you for your help.

You habe 2 choices:

Download another media player such as VLC, MX Player, etc, then test the videos with them to know for certain if the problem is isolated to only the native video player or not. These apps are better than the phone native video player, come loaded with more codecs and can play more formats. However, you said you didn't want this solution.
Convert the videos to the appropriate codecs, resolutions, bit rate and other parameters recognized by the phone's video player. You will have to 'duplicate' the playing video parameters to the non-playing videos by checking the differences between them. Then, you can convert them on your PC before transferring them to the phone.


text:
What is wrong with my Galaxy Tab A model SM-T380A
Galaxy Tab A Model SM-T380 will not shut off and has info on screen such as Odin Mode ( HighSpeed) Current binary, system status, FAP LOCK, OEM LOCK, WARRANTY VOID: 0x0, QUALCOMM SECUREBOOT, AP SWREV:S1,T1,R1,A2,P1, SECURE DOWNLOAD

If you dont know that, Its the download mode of Samsung phones. To get out of there just hold power button + home button + volume down if it doesn't work try holding all the buttons or volume up + power button + home button together.


text:
Can firewall block connection over VPN?
I would like to block specific apps from making connection to internet. I sometimes am connected by VPN but not always. How can I make firewall work for both VPN and not VPN, wifi and mobile data? My phone has root.

Since you have root, you can use AFWall+ which is based on iptables. It doesn't require VPN, so you can use VPN apps freely.

Android permits only one VPN to be working on the phone and that is the problem since firewalls also usually create a VPN and you are forced to switch off the VPN to make the firewall work.
However, there is a workaround, at least in some cases. I use Adguard which is an Adblocker with an integrated firewall. It creates it's own VPN on the device locally to filter ads. I also use Keep Solid VPN which is set to always use in my settings (Pie) . Adguard has a proxy mode which permits both VPNs to be used and since your device is rooted, it is easier.
However, note :

All VPNs may not work in this fashion. Check the Adguard forums.
In proxy mode, the efficacy of Adguard firewall is reduced but in my case I have no problems in blocking internet access to apps.
If I want only the Firewall functions but not Keep Solid VPN, I simply disconnect it from the notification panel.

To sum up, it's possible but you need to invest time in checking and ensuring both work.


text:
What is this icon in my status bar that looks like a finger pointing at 3 horizontal lines?
Can anyone identify this icon?

here again with context:

I can't find anything online and no one at Verizon or Kyocera can identify it either. I need help figuring out what this icon is and what it means.
I have contacted the Verizon Tech's, Kyocera and personally searched online, with no positive ID. Deleted all apps, factory reset, and even safe mode start up, and the icon remains at the top of the screen in the status bar. The only time the icon is not at the top of the screen is when you click on the drop down for the status bar icons. This phone is the newest Kyocera Duraforce Pro-2. Glove mode nor the underwater camera mode have any affect on the icon when switching these two selections on or off.
Any information on what this is would be greatly appreciated. Thank you for your time and help with this.

I mailed Kyocera linking this question and they replied very quickly.
It is a Verizon security app and Kyocera can't do a thing about it. Mail extract :

Allow us to inform you that this Icon is for a Verizon security application running on the phone, please be aware that this will not affecting its functionality. At the moment there is no way to remove the Icon.

Screenshot of mail below. You would need to chase Verizon for more details as to what it does but being a device tied with them, I guess you have to live with it.

(Click to enlarge)
You can refer to the Tech Support Case Number: 00689640
 and follow up with Kyocera (Phone.Help@kyocera.com)
 if you wish (The person who sent the email is Karla H, Technical Support Specialist).

Go into accessibility and turn off the "security and privacy" app and the icon will go away.

I went into accessibility and turned off "Digital Secure" and the icon went away.

Go to settings, apps and notifications, and then down to digital secure or safety and security and click on it. Then turn off all notifications and force stop it. The symbol should go away.

But have you told us What It Is, and the ramifications of shutting it off? It may be under Security for a reason. Just turning off a fire alarm doesn't shield you from fire.


text:
How to permanently erase the deleted files from Nexus 6p?
I had deleted several files like from my Nexus 6P, I want to permanently erase all deleted files, how to do it? where are the deleted files stored?

They are not 'stored' anywhere. The system marks them to be overwritten, so whenever that disk space is needed, it will write to it. There is no specific location,nor a way to trigger the overwrite. It'll happen as your device is used
Short of professional recovery tools, there is no way to get these files back especially as Android by default encrypted your phone
If you are really concerned, there are PC apps that can military grade format your phone


text:
What happened to the sound profiles that were in Lollipop?
I recently bought a new phone to replace my old one. The old phone is running 5.1 (Lollipop) and has "Predefined [sound and notification] profiles" (see screenshot). However, there seems to be no equivalent in 8.0.0 (Oreo), and as a result this new phone has been sitting on my desk all but unused for almost a month now.
Searching around it would seem I have to install some overly convoluted app with features I don't need (or want) to achieve the same result, but that can't be right, can it?
I don't think I need to explain what I want to accomplish, but in case I do and in case my twice-daily routine triggers someone to suggest an even better solution: I have one email account (of four set up in a third-party mail app) that I need to alert me 24/7. Nothing else needs my attention 24/7. So every time I go to bed I turn off notifications for the other three email accounts, turn off notifications for the phone, turn off notifications for text messages, turn off notifications for BBM, turn off notifications for a VoIP app and set my sound profile to "sleep". The sleep profile has all sounds and vibrations turned off so that, other than the very occasional sufficiently important incoming email, my using the phone won't disturb my wife. In the morning I reverse all of that.
I'd be happy with just having the sound profiles back -- the twice-daily routine is a bit tedious and ridiculous, it seems to me, but it's not that onerous -- so that's the main thrust of this question. Thanks.
Screenshot of "Sound & notification" profiles in Lollipop:

I've been looking at this some more -- because I hate installing more software than is actually necessary on any device or machine I own or manage -- and I figure that I should be able to allow my email app to override "do not disturb" to achieve what I want. I'll experiment further.

OK, so after putting down Android for what seemed like a step backwards, perhaps the Android developers are smarter than me. All of the below applies to Oreo (8.0.0).
The solution to this is as I suggested in my comment above, and that is to allow whatever app (email in my case) from which you want to receive notifications while the phone is in "Do not disturb" mode to be able to "Override Do not disturb". You can access this as follows:

Long-press the app's icon.
Tap the circled "i" icon in the menu that pops up.
Tap "App notifications".
Tap "Message notifications" (the actual words, not just the on/off toggle).
Tap "Override Do not disturb" to turn it on.

Another way to get to step 1 above is:

Open Settings.
Tap "Apps & notifications".
Tap "App info".
Tap the app in question.
Carry on as above from step 3.

Of course, you also need to configure how you want notifications -- the sound, vibration, notification dot, etc. -- and probably set up some options in the app itself.
You also need to ensure that your "Do not disturb" mode is set to "Priority only". On my phone the default settings for that mode are that "reminders" and "events" are both toggled on. I'm not sure if this is relevant, but I mention it in case it is.
I realised after I had decided to use two apps for email -- the one I have used for the last couple of years (K-9 Mail) for my "ordinary" accounts and the new one (Aqua Mail) for my priority email account -- that you may actually be able to configure Android to allow only one of your multiple email accounts in the same app to "override do not disturb". However, I didn't go that route.
Hope that helps someone.

What happened to the sound profiles that were in Lollipop?
  Unless I am mistaken, they have been removed on Android 8.
The sleep profile has all sounds and vibrations turned off so that, other than the very occasional sufficiently important incoming email, my using the phone won't disturb my wife. In the morning I reverse all of that.

You can a rule (actually 2) to achieve what you describe:
Goto Settings -> Sounds -> Do Not Disturb preferences.

The first rule will be a Time rule. Add a new Time rule or you can modify the existing Weeknight rule. You select the time, date when it should apply, set the preference to Total silence.
The second rule will be an Event rule. Add a new Event rule or you modify the existing Event rule (you can change its name). In "During Event for", select the email address it should apply to. In "Where reply is", select "Yes, Maybe or Not replied" date when it should apply, set the preference to Total silence.

Searching around it would seem I have to install some overly convoluted app with features I don't need (or want) to achieve the same result, but that can't be right, can it?

It is right, to have the sound profiles or something that looks like it, you will have to install a 3rd party app. I can try Sound Profiles (+ volume scheduler). Give it the appropriate permissions and you can use it to manage sound profiles again.
Disclaimer: I am not related to the app developer(s).

Thanks. Unfortunately a time rule won't work for me, as my hours are not consistent. I suppose I will need to look into that app and others and come back with feedback. Seems like such a stupid step backwards for Android.


text:
My Samsung Galaxy GT-S5830i wants to force stop everything
The phone starts up normally and then when I enter my password but then I am immediately greeted by: 'Sorry! The application (process com.android.) has stopped unexpectedly. Please try again.' and a Force close button underneath for every service and application.

this can be a software issue or even hardware issue. Did you try flashing it?

I haven't done anything to it at all I did was take a picture on whatsap and it stopped so I took the battery out and put it back in and from then on this has been happening.

So you need to factory reset it then. Use key combo (Volume up + Home while powering up)

That is what I have been doing.

this seems likely a hardware issue. you should bring the phone to a repair shop, they should be able to fix it

Okay thanks for the answer I ordered a new one for less than it costs to repair it now but thanks anyway :)

Let us continue this discussion in chat.


text:
How to share clipboard between Android devices, preferably without need for internet connection
Is there a way to share the contents of the clipboard between Android device similar to how it is done with Windows?
Basically I am looking for a similar method as asked here: How do I copy text from my PC to my phone?, but I want to to this with my smartphone (running Android 7.0) and tablet (running Android 4.3).
From the post above (and many others already posted on Android Stackexchange) there are many tools to do that with Android/Windows devices and I use Clipsync for that, nevertheless I was unsuccessful when I tried to setup with Android/Android devices.
Things I have tried

I recently tried to do that with Join but its is not working and I can't login to access the features (also it needs internet).
Also I tried to use Roamit which looking promising but it is not supportes on Android 4.3 devices.
I tried to setup Autoremote with Tasker as described here but I am stuck in setting up the task.
I was hoping to also use to QR code method but couldn't find a working one

I am looking for a method that uses bluetooth/local access to share clipboard contents between android deviceswith no creation of additional files such as .html files.

I recommend Clipboard Actions & Manager also on Izzy's list. It can transfer the content of the clipboard via Bluetooth and more. A html file will be transferred between the devices with the clipboard content.

@ReddyLutonadio thanks but I was hoping for an option which doesn't create additional files like .html, something more like clipsync

Thanks to Izzy's trove of curated apps
Paste Easy (that can be downloaded from Aptoide) was suggested. Reason being that this app caters to early versions of KitKat which is OP's requirement. I didn't try the app but OP has confirmed that it meets the bill.
For alternatives, see Multi Device Clipboard
on Izzy's list.


text:
Orange state: can't boot into fastboot after bootloader unlock (REALME 1)
Can anyone help me with this? I unlocked my bootloader successfully. But after that, when I am trying to get into fastboot mode, I am not able to do so. Whenever I run adb reboot fastboot, phone restarts and on the restart logo screen, I get a message saying:
Orange state- this device can't be trusted as it is unlocked. Reboot in 5 sec

And then, the device gets booted to normal mode. I even tried to rerun the in-depth app to get into fastboot mode, but that also not redirecting to fastboot mode. App says: You can only apply to exit in depth test after carrying out bootloader lock operation in fastboot mode
Now, the problem is if I can't go to fastboot, I can't flash anything and I can't relock my bootloader. Any help would be appreciated.
P.S I already enagle usb debugging after unlocking the bootloader and I could see the device in adb devices command.
Following this to unlock bootloader

Please include your phone model and Android version in the question. Maybe there are other users who had/have the same device and can help with the extra info.

Bootloader unlock feauture came yesterday for this phone. Though I just updated the question with phone model

adb reboot fastboot is not a command. You just rebooted into the system not the bootloader.
The adb command to get into the bootloader is:
adb reboot bootloader
or
adb reboot-bootloader

Have you tried enabling OEM unlocking on developer options? If you disabled it after unlocking bootloader then flashing is not possible on other phones it locks the phone at splash logo and required to flash the whole phone using a flash tool or maybe you disabled OEM unlocking after unlocking bootloader, Is your device factory reset after unlocking bootloader, or you miss a step in unlocking your bootloader
I recommend unlocking bootloader using fastboot

OEM Unlocking is enable. And device is successfully unlocked. I unlocked bootloader using fastboot.


text:
Factory reset from recovery mode not working on Samsung Galaxy GT-S5830i
I previously asked a question about my phone having a few issues with force stopping and I have tried to factory reset it from recovery mode lots of times but it just stays the same.

So, what is not working? The factory reset process or the issues not being solved?

It will not factory reset.

But becuase it does not hard reset it does not resolve the problems.

plz answer this question i have a really important phone number on there and i cant get it off because i have a chromebook!

huh... what is happening when you boot to recovery? Can you see the option for resetting? Or you are unable to boot into recovery? Remember, you'll lose  everything stored in the phone.

I am aware that I will lose everything in storege but I have the only thing I really need off of it; I am just trying to prevent having to buy a new one. Everything seems to work fine apart from when you boot it up it is exactly the same as before.

Hum... I think your file system has somehow turned out to be read-only that can explain everything returning back to previous settings. This happens when the memory chip is damaged


text:
Where do the exact locations of the phone buttons combinations stored?
Where do the exact location of the phone button combinations like power reset while holding Volume down + Power, booting to recovery by holding Volume up + Power + Home (if there is a Home button) is it on the system, system partition, boot partition, any other partition, etc.

Your device's primary or secondary bootloader would contain the key combination for booting into special partitions.

That's what I thought in the first place. But can we modify it?.

I don't know whether this is possible without having the source code. OEMs don't provide source code for bootloaders

It's not stored in the Android system, but somewhere in the phone's firmware that's not modifiable.
Such functionalities like hard poweroff or hard reset is controlled by the underlying hardware directly, not by Android system. Therefore the button combos are stored in the hardware controller and are usually not modifiable by software.

Cool thanks, it would be so cool if you can modify that where you can boot to your recovery in an emergency situation such as hardbricking or some other stuff.

There usually are internal ports for special rescuing devices to connect


text:
Why does the number of available CPU cores change when an app is closed?
To find the number of cores available to you in Termux you run:
grep Cpus_allowed /proc/self/status

This number of cores is limited in a similar way to running taskset on GNU/Linux.
I am trying to be able to predict what that will return.
According to the app CPU-Z my phone (Huawei Smart P) has 1 HiSilicon Kirin 659 with 8 cores. According to the app CPU Info 4 cores are running the same speed (480-1709Mhz) and 4 cores are running the same speed (1402-2362Mhz).
After booting the phone and waiting 5 minutes to make sure all startup tasks have been started/completed I started Termux, login through ssh and got:
Cpus_allowed_list:       0-7

Which is exactly what I expect.
But if I press the home key, I get:
Cpus_allowed_list:      2-3

I thought this might have to do with how hard the cores are loaded, so I switched to Termux again, started 16 bzip2s. This does not change the number of cores I get immediately. But after 30s I get 4 cores:
Cpus_allowed_list:     0-3

And yet later I get bumped back to 2 cores:
Cpus_allowed_list:      2-3

This behaviour happens through ssh whether Termux is in the foreground or background.
The effect of the home key is only when running Termux: If I run CPU Info, then press home and then start Termux, then Termux still has 8 cores:
Cpus_allowed_list:       0-7

Only when I switch away from Termux using the home key, the app-list key, or the back key does the number of CPUs change.
Software controlled big.LITTLE could explain going from 8 to 4 cores if the limit was not enforced immediately after boot, but only activated later. Since the limit is not activated 5 minutes after boot, I think it is safe to reject this as the explanation. Also it does not explain limiting to 2 cores some of the time when running 16 bzip2s.
What is causing the phone to limit me from using 8 cores? How can I tell the phone not to do so? What is causing the limit to jump between 2 and 4 cores at seemingly random intervals?
(On top of this I had expected the cores to run at 100% speed which also does not happen).
The limitation does not happen if not run through ssh or if run in a tmux session where the tmux session is started via the terminal on the phone.

The CPU is an Octa core with BIG-little concept. Therefore this answer also applies to your CPU.

@Robert IF it was a big.LITTLE CPU why do I get 0-7 after boot? It stays that way if I do not press home. top clearly shows 8 CPUs running 100%. Also that would not explain why I am limited to only 2 cores some of the time.

I would assume that the device starts without specific CPU assignments. This also makes the boot as fast as possible. Afterwards (may be by the start of a special service) it applies the power configuration to limit the power consumption. New processes start with 2 cores and after 30 seconds of high cpu usage all 4 fast cores are allowed. Keep in mind that Smartphones are optimized for UI responsiveness, not for max CPU throughput.

@Robert I have updated the question. The big.LITTLE explanation does not seem to fit the evidence.

What is causing the phone to limit me from using 8 cores?

Linux Control Groups (cgroups). Android uses them to control how much resources a process can use. In particular the processes of apps are assigned to different cgroups depending on their lifecycle, which usually depends on the app's interactivity with the user.
For instance an app being actively used in foreground needs more processing power than the one staying idle in the background. So Android creates multiple descendant sub-cgroups for different states of the app (and non-app) processes:
~# grep . /dev/cpuset/*/cpus
/dev/cpuset/background/cpus:0-1
/dev/cpuset/foreground/cpus:0-6
/dev/cpuset/restricted/cpus:0-3
/dev/cpuset/top-app/cpus:0-7

cpuset is one of the multiple types of cgroups Android uses for different purposes.
As you can see that the apps in background are allowed to use only 2 (out of 8) CPUs, those running a foreground service can use 7 CPUs, while the top apps can use all CPUs. Android framework continuously switches the PID of an app between these sub-cgroups as the app changes its state.
Note that:

Different vendors may configure the cgroups differently depending on the number of available CPU cores on the device.
Setting CPU affinity of a task using taskset is filtered to just those CPUs allowed in that task’s cpuset.

How can I tell the phone not to do so?

The best way would be to modify the code and rebuild the ROM so that it no more uses the cgroups (or uses them the way you want). Or simply change the CPU values in the files shown above, hoping that they won't revert back.
But for a normal user this would do more harm than good, consuming more resources and badly affecting the device performance.

Related:

Android stops/pauses execution of my background script?

u0_a164@localhost:~$ grep . /dev/cpuset/*/cpus gives grep: /dev/cpuset/*/cpus: No such file or directory

@OleTange filesystem might be mounted somewhere else. E.g. in /sys/fs/cgroup. Check with mount | grep cgroup. Also you might need root privileges or permissive SELinux to access the directory.

Summary: the more cores you use the more battery you consume so CPU hotplugging turns off the other cores, and the others do the work which makes them at 100% CPU usage, which also give the best performance and the most balanced one.
It's CPU hotplug It turns on and off the cores when needed or not.
It's running 100% CPU usage because it's like this. Imagine, there's a 4 car, and let's assume the drivers are the cores. You have four lanes and 4 cars of course. Each one of them will take 100 pizzas. You can let one  core to do all the work and that's what hot plugging do. Knowing that a car with 50 pizzas consumes a lot less fuel than a car with 100 pizzas you can now see how we can have the same performance and save on fuel: load two cars with 50 pizzas and let them accelerate as quickly as possible to the destination (performance governor). They will get there as quickly as one car with 100 pizzas (same performance), but burn less fuel (battery saving).
If you want to make your phone run at 8 cores then you need to install a custom kernel, use an other CPU governor, use a custom CPU hotplugging, or without installing a custom kernel use an interactive governor, then tweak its parameters.
You can search on XDA for Advance Interactive governor tweaks.

Further, what do you think gives "best balance performance" on high load? Certainly not disabling cores. And 16 bzip2 processes certainly need more than 3 cores for "good performance". So could you please explain – and back your claim?

Use an interactive governor then tune its parameters

Its the way your kernel turn on and off the cores if its needed or not in the bootup all cores are on because android bootup are sometimes slow so developers try to turn on all the cores to make it boot faster


text:
Does Android supports .wav audio?
In many internet blogs I read that wav audio files are not supported by Android OS. I have also tried to play .wav audio files with the default music player software in Android, but it couldn't be played.
But, recently when I peeped into the media folder in Android's system partition, (/system/media/alarms), I found many .wav files there.
Now I am confused. Does Android supports wav files ?

What's the Android version and the phone model?

Micromax Bharat 3 Q437

Yes, Android supports .wav audio files.
The Supported media formats lists the audio & video formats supported by Android, and .wav audio is among the many listed.
Supported file type(s) / Container format (only audio file types are listed below)
 • 3GPP (.3gp)
 • MPEG-4 (.mp4, .m4a)
 • ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)
 • MPEG-TS (.ts, not seekable, Android 3.0+)
 • FLAC (.flac) only
 • GSM(.gsm)
 • Type 0 and 1 (.mid, .xmf, .mxmf)
 • RTTTL/RTX (.rtttl, .rtx)
 • OTA (.ota)
 • iMelody (.imy)
 • MP3 (.mp3)
 • Matroska (.mkv)
 • WAVE (.wav)
 • Ogg (.ogg)
 • Matroska (.mkv, Android 4.0+)

But as I had mentioned, that I was unable to play .wav files using the default music player. Are there different types of wav codecs ? OR is the default music player app doesn't support wav files ?

Try another music player (VLX, MX player, etc), and test if it can play or not.

Yes, those can play wav audios.

Then the problem is with the native music app on your phone. Because as the link provided in the answer, encoding wav is supported since Android 4.1 and decoding has always been present.

Understood. Thanks for your response. Have a nice day :)

The specifications of your phone show that it is able to handle wav audio (on the page go to "Audio file formats/codecs"

If my answer is satisfactory, you can mark it as an answer


text:
Skype message to open local video file
I'm using Skype on Android 7. I have stored a video locally on the phone on the location /storage/emulated/0/myvideo.mp4.
How can I send a skype message (from another device) so that on the above mentioned device the video is opened? That means I would like to send a message containing a hyperlink to /storage/emulated/0/myvideo.mp4 and when clicked on it the video should open.

How long is the video. According to the Skype documentation only videos of less than a minute can be shared: https://support.skype.com/en/faq/FA34718

@Robert The video is 5min. Actually I don't want to send the video over skype. I just want to send a link to the video which is already locally stored on the phone.

Links to local files on your phone only work on your device, not on other devices. If you want to share your video you have to send it via Skype (if it is less than one minute) or upload it somewhere and then send the online link via Skype chat.
Only if the both phones are next to each other an app that uses local sharing can be used, but that does not work with Skype.

Let's assume the video is in the local storage of device A. Device B sends a skype message to device A to open this video. So when device A opens the link the video is played. Do you see what I want? ;)

@machinery What you want is clear, however you can only use what has been implemented in Skype. On Skype for desktop there are some workarounds to send a video as live stream instead of the stream of a webcam (that would be the closest solution to what you have asked), however those hacks are not possible on Android.


text:
FRP and OEM locks bricked my Samsung phone after root
I recently flashed my SM-J701F (Samsung Galaxy J7 Nxt, Android 8.1) with TWRP and Magisk.
Both OEM and RFP locks somehow turned themselves on when I tried to reboot, effectively bricking it by leaving me unable to either boot into any mode or flashing anything using Odin. (Odin always returns FAIL)
It's now asking me to use Smart Switch's emergency recovery feature, but that software refuses to recognize my device too.

Can you link to instructions you followed for installing and Magisk, and did you deviate from them (perhaps by skipping something)? @BoLawson the boot process would have failed due to twrp and Magisk (device integrity failed), so OP cannot really boot into either of them, thus having access to root is out of scope here.

@Firelord my mistake, you are correct. // Flashing stock Samsung factory signed firmware of the current or updated android version should not be stopped through odin by the OEM lock. Leading to when Odin fails does it just say fail (if so what point?) Or is there an error along with it like REV. CHECK FAIL(BOOTLOADER) DEVICE: 8, BINARY: 5

Base on my research you can fix the OEM lock by flashing Samsung stock signed firmware using Odin or Samsung tool pro. To remove the frp you need to create a modded boot where the USB debugging is on. You can make one in assayyed kitchen you just need your stock boot, you can get stock boot at the firmware files, let's assume you flash the modded boot. You will boot to your phone but the frp locks is still there what you need to do is connect your phone to your PC then open Samsung tool pro find your phone model there then remove frp using adb.
P.S. Factory data reset your phone after flashing modded boot (optional)

At this point, you will either have to talk to a professional or buy a new device.
This is called "bricking" a device: it's now useless, except as a pretty weight. Your phone is soft bricked: possible to recover, but not guaranteed.
There are no conventional methods left to you. Factory reset through recovery isn't an option, fastboot isn't an option, and neither are most standard tools. And you said Odin is not working
Both of my options will cost money, but a professional phone repair person will have access to better tools than you. On that note, it could be costly and even they may not be able to help you. Availability of these services depends on where you are, and your budget


text:
Will skipping Play Store updates cause problems?
I have found that auto-updating apps from the Play Store sometimes causes me an inconenience: A newer versions of an app sometimes doesn't have the features I liked in the older version. Thus, I selectively update my apps
I'm wondering what happens in this scenario: Let's say I download an app today, call it version 1.0, that I do not auto-update. An update to 1.1 is released some time later, then a release to 1.2, then 1.3 etc. So let's say I decide to update when 1.3 comes out. Does updating then cumulatively capture changes from 1.2 and 1.1 as as well? Or have I missed functionality in 1.1 or 1.2?
Put another way, I would assume an update at that time would make that app identical to what is available on the Play Store that day. Is that correct?

This is not about Android apps per se, but about softwares in general. Whether you make incremental update (say 1.3 to 1.4) or full update by skipping some versions (say 1.1 to 1.4), you finally end up with same version which would offer same functionality. The difference is that the changelog which shows the changes that took place in the most recent version is written  in comparison to last revision. Thus, when skipping updates you would want to read all the changelogs available in between to get a full idea of what new features or lack of feature are available to you after the update.

Android applications are used to perform a task or a  group of tasks. App updates are additional features that are added to the current version of that app. An application has several states while running on mobile such as start, stop, resume, terminate etc.
Play Store is one of the secured source for downloading and installing android applications. A developer in play store will release two types of app(not for every apps).

Stable :
This version runs stable on most devices and may not have any app close or similar issues.
Beta :
Releases updates under development stages and not upto stable. User need to join beta program from play store.

So, if you have installed an app from play store, then you can run that app without updating for long time, because that is stable. The only thing you've missing will be updated features.  For example, Google phone app(say version 23). It had added new design few months ago, but if you're running version 22, you can use as long as you can. And you'll only miss new design, dark theme like that. And, if you're installing version 29, after skipping 23,24,.. , you'll get features of that versions, after updating to version 29. It's because android apps are developed  incremental basis( as Firelord mentioned below).
Also, there are some apps which requires strict updates. Example, WhatsApp. WhatsApp will check the current version of app and prohibits app usage until app update. This occurs because WhatsApp may stop support specific version after few months(may be yearly, you're redirected to  play store while opening WhatsApp).
System apps may get auto updated during OTA/ security updates released by manufacturer.
If you're installing an app from play store today, you're installing today's latest stable version.


text:
Google Play Music keeps putting non-music audio files into my music library
So now all of my audiobooks and ring tones are in there with my songs and there's no way to seperate them even though I keep my music, audiobook and ringtones in separately files on my SD card.

Move all of these non song files to a specific folder on your SD card, and create an empty file in that folder called ".nomedia". This tells Android not to scan for media there


text:
How do I stop ads interrupting my music player
I have a Galaxy Note 9 where I usually have music playing in Amazon Music Player in the background while I play games. In the old version of the OS (Samsung's version Android 8.1) when I am playing a game and an advert starts, it would pause the music, but I could just slide down the notification area and unpause it. Since the recent upgrade to Android 9 (again Samsung's version which it automatically upgraded to), I have to wait until the advert has finished before I can unpause the music. This is ultra annoying!
I don't mind the advert, or even the advert playing its sounds while the music is in the background, but completely taking over the sound like this just wrong!
So is there a setting or app-permission or anything I can change to disable ads from stealing exclusive access to the audio?

Are you against using a third-party apps to disable ads, such as through an ad-blocker?

If it comes to that, then I don't mind installing them.

Open the Google Settings app on your device (called Google Settings or Settings, depending on your device).
Scroll down and tap Google.
Tap Ads.
Turn on Opt out of interest-based ads or Opt out of Ads Personalization.
Reset the ad id, or user id.
This is the only thing I've been able to find on the subject.  Like you, I run a background app while doing other things and, knock on plastic and glass, it seems to have worked
I have an S10+, but it should be the same on your note

This would not affect sound in ads so not help to stop ads to mute music.

If adblock is an option, I highly recommend Blokada. It is a local VPN that uses host files to block ads and can work without root. More info here. (I am not affiliated with it). It sounds easiest just to block the ads
However, there is no way to keep an app from stealing audio focus that I am aware of.


text:
SwiftKey: Keyboard completely gone after update!
To all SwiftKey users who stumble accross this post: Do not update your SwirftKey app at the moment!
Hello everyone
Today I updated several apps on my Android 9 Huawei Mate 20 Pro (non-rooted), among them also the SwiftKey application. After this update my keyboard was gone, completely. Unfortunately I had the great idea that this could be solved by restarting my phone. But after the restart, when asked for the password (the entering of the pin worked fine; there was a numpad) there was and is no keyboard to enter anyting. i.e. the password.
This issue renders my whole device useless. In addition I have no clue on how to solve this and even if I did, I wouldn't be able to access my phone in any way (I think? Because even a connection to a computer would be denied without allowing USB debugging... Am I right?) - e.g. update SwiftKey again. SwiftKey is the stock keyboard of the Huawei Mate 20 Pro...
I wrote something very similar on the SwiftKey "Support" Page (here) - which is a community-help-itself-site, i think. (It's incredible that there is absolutly no possibility to contact SwiftKey directly, or am I mistaken?) But I thought the kind people here might be (way) more competent, especially if will I have to access my phone through a USB connection without the possibility to enter my password...
Any help is greatly appreciated. :) Many thanks.

Solution:
Use OTG adapter with an external keyboard. For details see accepted answer and this Reddit thread.

There must be some other issue that caused your SwiftKey app keyboard to be disabled or uninstalled. I just updated mine (deliberately)  to version 7.2.4.22 to test this and the app is working fine. I also restarted the phone and it still works.
Here are some solutions I can think of:

If you had an another keyboard installed, such as Google Keyboard (usually comes with most Android devices that ship Google apps), and provided you didn't disable the keyboard under Available Keyboard settings, you should be able to boot into safe mode and use the device. The stock keyboard app would kick-in automatically. Search internet for safe booting in your device.
Alternatively, since your device supports OTG host you should be able to use an OTG cable with any standard wired keyboard to enter your password/PIN. For a pattern, use a wired mouse.

Thank you for your support and for trying yourself... I tried the first option (it's power and volume down button or volume down button alone [?] after a reboot), but this sends me right back to the password screen... Am I doing this right? The Huawei support recommended wiping the cache (Vol. up, down, Powerbutton after reboot), which didn't work neither. I've thought about your second solution myself and shall try that as soon as I've accuried an OTG cable on monday... Many thanks!

While browsing for that cable, it turns out that I don't know nothing about OTG: Can I just buy any USB C (male) to USB A (female) adapter or does it have to specifically support OTG? I.e. does the adapter have to have a OTG card (or similar) in it or is a plain old USB-A-to-C-Adapter sufficient?

@JoeHammer I suggest you consider buying one which explicitly supports OTG. I don't know whether both type of cable works, so I'm recommending a safer option here. As for the key combination, I'm sorry, I don't know which one would work. All I know is that if your key combination work and you end up with a screen to enter your pin/password, somewhere it would show "safe mode" on the screen.

Alright I'll consider buying one that supports OTG explicitly or I'll get advice from the store personel... As for the key combination: That's ok, I tried every combination, with three buttons there are only seven combinations. It turns out that (1) all three of them boot the device in a "EMUI"/OS update mode (according to Huawei support, this erases cache also), (2) volume up boots it into "ease mode" where you can do a factory reset (and also a cache partition reset...?!), (3) any other combination seems not do do anything - I never saw "safe mode" anywhere on the screen...

Addition: (4) Volume down button on start - the safe mode boot option according to the internet - seems also not to do anything, i.e. I end up at the same password entry screen as before, with no "safe mode" screen anywhere... I therefore don't know how to enter safe mode, or at least, if one of the combinations boots the device into safe mode, the mode is not indicated on the screen... Thank you, though! :)


text:
How to turn off auto rotation in aide
I am not able to turn off auto-rotation in aide app, i tried many times but i could not found any solution.
i also tried to find the option for rotation in aide setting but there was no option given as the same.
please help.
thank you.

Some apps enforce auto rotation. There is nothing you can do about that.
Make sure your device has it shut off. Should be a quick tile (slide down twice from top of screen) that had a phone symbol. Make sure there are no circular lines around it, and it is not brightened/bolded


text:
If an app requires no permission, can I be completely sure that it is safe to install?
I have an app that requires no permissions whatsoever. Please note that this app does not come from an official source.
Given that the app requires no permissions:

Can I be completely sure that it is safe to install?
Are there still ways in which this app might be harmful or malicious to my device, even though it does not have any permissions?

In an ideal world, an Android app that has no permissions would mean that the app can not seriously harm your device.
Unluckily we are not living in an ideal world, especially on Android where the device manufacturer often does not provide the newest security updates to each and every device.
Therefore running a malicious app without any permission on an Android device can end up in a permanent device infection if the device is vulnerable to an exploit that allows the app to get root permissions. Those exploits can work independently if your device is rooted or not, then work even on stock rom devices.
Therefore the risk executing an app without any permission depends on large parts if your device has the very latest security update (see patch level date in Settings -> System -> About -> Security patch level).
If your device has the most recent patch level and the app is not brand new the risk is low that the app is able to harm your device. However if your device has a security patch level months or even years ago even an app without permissions may cause serious harm to your device.
What is possible on different Android versions
There is an old article (2012) on AndroidPolicy: Security scare of the week: What can an app with no permissions do? which lists a few facts about what apps can do without any permissions. Lets try to check some of the facts and check them regarding modern Android devices:
Read data on your SD card
By default on devices prior to Android 4.4 apps had by default read access to the sd-card section:

This permission is enforced starting in API level 19 (Android 4.4). Before API level 19, this permission is not enforced and all apps still have access to read from external storage. You can test your app with the permission enforced by enabling Protect USB storage under Developer options in the Settings app on a device running Android 4.1 or higher. [source]

But even on newer versions there is still the possibility to get sd-card access "for free" in case the app defines that it was developed for some very old Android version. In such a case Android implicitly grants the sd-card read permission (untested: is this still true for e.g. an Android 10 device?)

Note: If both your minSdkVersion and targetSdkVersion values are set to 3 (Android 1.5) or lower, the system implicitly grants your app this permission.

To avoid misuse of those "implicit permissions" Google enforces a certain targetSdkVersion when uploading an app to Google PlayStore [source]. Hence if you have an app from Google PlayStore that has been published in 2018 or later (latest update) those implicit permissions on the sd-card are impossible.
Read installed apps via /data/system/packages.list
-> TBD
Miscellaneous data from /proc
Android ID, kernel version, and ROM version
-> TBD

+1. Do you know if an app which doesn't require a permission can cause the default browser to launch a spammy link which may be containing a malware?

@Firelord Yes that works, just verified. Therefore you could also use it for sending data URL encoded to any server you want (if a default browser is set).

Hey Robert. Do you think you can find time to take a look at this article and see if any of the issues still exist with recent version of Android? I don't think the article is of much use, but incorporating anything of importance from there into your answer would be good IMO. :)

@Firelord I have updated my answer with the claims from the article and some details I knew on the sd-card topic. The other claims I am not very familiar with. May be someone other can provide this info.

Thanks. I tried to do some testing but couldn't find a suitable app. And the results I got from Terminal Emulator app are something I'm not sure I can use (because OP said no permissions app, but TE does asks some permissions) here. Nevertheless, I could list the kernel version /proc/version, ROM version, execute getprop and get rich details,  cpuinfo (/proc/cpuinfo), but /data/system/packages.list was not accessible even though /data/system directory items could be listed.