15

Is it possible to automatically power on the device once the charger is connected given that the device is initially turned off?

10

The battery charging graphic is displayed by /system/bin/playlpm file on Samsung devices.

If you are root, you can edit this file to:

#!/system/bin/sh
/system/bin/reboot

And be sure to add those permissions to the file:

chmod 0755 /system/bin/playlpm
chown root.shell /system/bin/playlpm

Your device will now boot when plugged

  • Thanks @IET_DEMO , Do you know solutions for cyanogenmod devices to do this? – m0j1 Apr 5 '16 at 20:54
  • Hi, I have a Cyanogenmod device , do you know how can I do this on cyanogenmod ? Thanks – m0j1 Apr 20 '16 at 2:34
  • This only works on Samsung devices. This may be useful for you – IET_DEMO Apr 20 '16 at 13:56
  • If you're trying to do this, make sure you don't have carriage returns in your playlpm file or it won't work. – ZorroDeLaArena Oct 4 '16 at 12:38
2

Just got this working for ZTE Force (Boost Force, Sprint Force, etc).

I used IET_DEMO's answer, but replaced the file located at /system/bin/battery_charging with this code:

#!/system/bin/sh
/system/bin/reboot
  • Hi, I have a Cyanogenmod device , do you know how can I do this on cyanogenmod ? Thanks – m0j1 Apr 20 '16 at 2:34
2

For some older Samsung devices, this can be accomplished through NoMoarPowah!:

NoMoarPowah! can automatically reboot into Android when charging is done. Either when fully charged, or when the battery level reaches 15% and Android has enough juice to run.

You need root and you probably don't want to do it unless you really know what you're doing, since I would expect this to modify important system files.


It looks like this has been removed from the Play Store, but you can probably find the APK hosted elsewhere. (I don't have a trusted link offhand.)

1

If you want to do the opposite, shutdown when charge, use this: "Auto ShutDown when no charge" https://play.google.com/store/apps/details?id=com.zeroFactorial.probattle good for my car's device and also had button broken

0

Kernel is loaded at a later stage in the boot-up process, so any modifications to it would not have any effect for when the device is powered off.

This functionality really depends on each device's hardware, most likely in the bootloader (more knowledgeable editors feel free to correct me.) For example, my Motorola Atrix 4G phone begins booting up when I connect a charger, while my Samsung Galaxy Tab does not - it displays the "Battery Charging" graphic and requires being powered on manually.

  • 2
    so what brings up the Battery charging graphic on the screen ?!...now the bootloader is called when you hit on the power button manually, but what piece of code displays the battery charging graph on the screen ?! – Muhammad Ghandour Mar 4 '12 at 9:19
0

So, there are many ways to do so. The most proper one, as always supported by Google (and more and more by others, e.g. nvidia from nougat) is this fastboot command

fastboot oem off-mode-charge 0

Otherwise, you can either hijack the charging binary (not guaranteed to be possible on all devices, but just requires root) or patch your ramdisk (theoretically universal, but will require an unlocked bootloader).

For the first solution, you'll have to find somewhere in your system partition (usually the bin folder) where the program in charge of the battery animation and all resides. Some common names:

  • Motorola: charge_only_mode
  • Mediatek: kpoc_charger or ipod
  • Htc: chargemon or zchgd
  • Samsung: playlpm or lpm
  • Sony: chargemon or battery_charging
  • Most(?) AOSP-based roms: healthd

Once found, you can just replace it with a script such as that above by IET_DEMO.

Touching the kernel is instead something I don't feel like explaining and recommending if you don't know what you are doing.

Just for the records then, I'd just like to underline that offline charging exists because the boot process is fairly energy intensive, and especially on older phones without even fast charging the power draw from the system could be higher than that on the plug.

protected by Community Apr 24 '15 at 12:43

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.