On (at least) some Samsung devices there is some piece of software that runs when the device is turned off. It is the one that displays the battery state when charging, along with the red/green indicator light.

It is obviously tiny, native and device-specific. It is also probably (again, at least) somehow related to the initial bootloader that e.g. puts the system in recovery mode if needed.

But would it be possible to modify that piece of software to, for example, change the light colors or other functionality? I'm really asking just in theory; even if extremely hard and non-practical, I'm curious if it would be possible.

EDIT: Just clarifying here, but I mean the software that runs when the entire device is turned off, not just the screen. I have a Galaxy S3 LTE (GT-I9305, CyanogenMod 10.1, CWM recovery 6.0), and CyanogenMod actually allows me to change the light colors when just the screen is off.

Also, I don't necessarily want to change it by any means, I am just curious if it could be changed.

Here's what the software I mean looks like on my phone (sorry for the poor quality, obviously not taken with my phone :P):



Have your tried using Custom Roms... I believe AOPK and some others support light changes... Check it out :)


  • I am running CM10.1 (you sadly don't have CM11 for GT-I9305 yet) and CWM recovery 6.x, but they at least don't modify it in any way. – PurkkaKoodari Jul 31 '14 at 7:16
  • Ahh... you might wanna state to the developers (of CM for example) for the feature your require. Not too sure if they find any value in changing the colour of the light while in sleep mode but it would not hurt to ask them).. I am still learning development myself so I cant give you a definitive answer at this stage other than try another ROM which does have a feature to change the light..BUT even saying that the change light feature within AOPK is only when the mobile phone is awake and receiving notifications. – Rushnosh Jul 31 '14 at 7:58
  • I'm not sure it is related to the ROM. I do not mean the stuff going on when the screen is turned off, but when the entire device is turned off. I updated the question for clarity. – PurkkaKoodari Jul 31 '14 at 11:01
  • Also, I don't require a certain feature, but I'm curious if it was possible to change the software causing said light to appear. – PurkkaKoodari Jul 31 '14 at 11:09

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