Samsung Galaxy S3 Mini provides a mechanical home key. This key also wakes the device up when it is in standby mode, identical to the power key. Sometimes you may not want this feature.
When using tools like NoLED this is quite useful since the power key does not work with active notifications (the device is already “awake” and the display will just be turned off when using the power key in this situation). Even though it is possible to use the “back” key or the menu key depending on the setting in NoLED.
When carrying the device in a trouser pocket it may happen that the home key gets pressed unintentionally and maybe the display gets unlocked. Besides the higher power consumption for the active display it also may happen that unintentionally input on the device will occur. I have experienced more than once that an app was active or that settings where modified as I took the supposed “locked” device out of the pocket.
One solution is to set a password or pattern to unlock the device – even if the display turns on in the pocket the device itself stays locked. But this does not change anything for the energy consumption for turning on the display. The direct access to frequently used apps using shortcuts and the direct access to the “power widgets” on the lock screen would also not be possible any longer.
Another solution is to disable the device activation through the home button which however requires root rights. The following description applies to the rooted version of Android 4.1.2 based on the original firmware by Samsung without any special optimizations. In principle this solution is also applicable for other devices and versions (for example Samsung Galaxy S Duos or the “regular” Samsung Galaxy S3).
I don’t take any responsibility to potential damages or failure caused by modifications of system files! Any modification at one’s own risk!
Open the directory
/system/usr/keylayout using Root Browser or TotalCommander. There you should find the file
gpio-keys.kl (for other models maybe
surf_keypad.kl) with about the following content:
key 115 VOLUME_UP WAKE key 114 VOLUME_DOWN WAKE key 116 POWER WAKE key 172 HOME WAKE
The crucial part is the line with the text
key 172 HOME WAKE – this defines the function of the home key and with
WAKE the function to activate the display. Here you have to remove the word
WAKE – maybe after creating a commented copy of the line (by the additional character
# at the beginning of the line followed by a space). The line must not be removed completely – otherwise the home key would not work at all any longer:
key 115 VOLUME_UP WAKE key 114 VOLUME_DOWN WAKE key 116 POWER WAKE # key 172 HOME WAKE key 172 HOME
After saving the file Android has to be restarted once before the modification becomes effective. By removing of
WAKE the device will now only be activated using the power key. Unintentional unlocks of the device in the trouser pocket should not occur any longer.
If you want to revert the changes just restore the entry in the file and restart the device.