Avr 132025
 

Despite latest tuning (see previous article), the battery drain was still there, less severe, but still..

There I decided to root the tablet and install magisk.

Download the APK, copy/paste it and rename it to zip and flash it with twrp.

Reboot and install the apk.

Launch the app and let it update the tablet and reboot.

Then install xtrem-battery-saver in magisk as a module.

Here below my config.

While on low power mode, we are changing the CPU governors to powersave (android should do that while on power saving mode but just to be sure…).

While on screen off, we are disabling cpu2 to 7 and setting cpu governors to powersave on cpu0 to 1. Also we setting lower priority on google play services. Last but not least, we are forcing doze mode to light.

This rather aggressive config paid off : i can spend a whole day on screen off without losing any battery power.

version=2
delay=3
log_file=/sdcard/XtremeBS.log
log_level=1

screen_off={
handle_cores=cpu0 cpu1
disable_cores=cpu2 cpu3 cpu4 cpu5 cpu6 cpu7
handle_gms=nice
kill_wifi=true
keep_on_charge=true
doze=light
}

low_power={
keep_on_charge=true
handle_cores=auto
disable_cores=false
handle_apps=false
allowlist=/data/local/tmp/XtremeBS/apps.allow
denylist=/data/local/tmp/XtremeBS/apps.deny
handle_gms=false
handle_proc=false
proc_file=/data/local/tmp/XtremeBS/proc.list
low_ram=false
doze=false
kill_wifi=false
}

charging={
}

manual={
}

boot={
}
Avr 132025
 

A few weeks after flashing lineageos 21, i started to experience a massive battery drain : the tablet would lose all its battery power while on sitting idle, screen off, wifi off, on battery saving mode.

Therefore i took a look at the battery stats:

adb shell dumpsys batterystats --reset 

then a couple of hours later

adb shell dumpsys batterystats > [path/]batterystats.txt 

also i took a look at the doze log :

adb shell dumpsys deviceidle 

Based on my reading, I disabled the following packages:

adb shell pm disable-user –user 0 com.android.phone
adb shell pm disable-user –user 0 com.android.dialer
adb shell pm disable-user –user 0 com.android.messaging
adb shell pm disable-user –user 0 com.android.cellbroadcastreceiver

And just to be sure these do not interfere with doze mode:

adb shell dumpsys deviceidle sys-whitelist -com.android.messaging
adb shell dumpsys deviceidle sys-whitelist -com.android.cellbroadcastreceiver
adb shell dumpsys deviceidle sys-whitelist -com.android.cellbroadcastreceiver.module
adb shell dumpsys deviceidle sys-whitelist -com.android.emergency

Fév 212025
 

I have a galaxy tab a8 for a few years now (and i previously owned many different models in the galaxy tab series).
I use it mainly for web browsing, social networks and mails.
I was never impressed by the performances from day 1 but lately the tablet was really laggy and especially from waking up the device : for a few minutes, the tablet was barely usable.

So i decided to flash it, here below my steps.

  • Ensure you have the latest « Android SDK Platform-Tools » (version 35.0.2-12147458 in my case)
  • Ensure you have the latest « SAMSUNG USB Driver for Mobile Phones » (version 1.7.61.0 in my case)
  • Enable oem unlock in developper options (dont forget to reboot and enter download mode to actually activate oem unlock / the tablet will be reseted to factory)
  • Enter download mode and flash twrp via odin (AP slot / Use the MrFlufflyOven twrp 3.7.1)
  • Enter recovery mode (twrp) and reboot to fastbootd
  • While in fastbootd mode, flash new image (in my case: fastboot flash system lineage-21.0-20250125-UNOFFICIAL-arm64_bgN-signed.img from andyyan-gsi)
  • Optional : If the flashed image is not lineageos, consider flashing back the stock recovery (extracted with 7zip from the stock image downloaded from samfw.com)

The tablet rebooted smoothly to lineageos and has never been so well performing : user experience has never been so snappy 

Reminder :

  • To enter download mode, hold volume up and volume down at the same time then plug your usb cable connected to your computer.
  • To enter recovery mode, hold volume up and power buttons.