I have decompiled system.img from the stock rom 1.10 to see what is inside in the hope to fix some controller behavior. I decompiled Gamepad.apk to see how it work too.
Gamepad.apk is writing to a file:
if you "cat" /sys/devices/soc/soc:[email protected]
the value tell you what controller mode is in use (0=PS3, 1=XBOX)
But this doesn't help me do remap the keys, it is used just to swap L/R and controller mode I think.
So I digged into the filesystem and found
Those file seem to map controllers button, and I want to tweak those file to see what happen, but I need to be root I think because the filesystem is read only and don't allow me to push any files here.
There is a way to use adb as root with the XDPlus ? I really want to check if I can get rid of the bad joystick behavior (like constantly looking up in minecraft when in XBOX mode, or allow minecraft to use the DPad in PS3 mode). All is perfectly fine with the original XD.
 I have checked the method to root the GPDXD Plus, but I would avoid to format my SDCARD since I use it as internal storage and have 50+GB of data it took 8 hours to copy all files on it.... :/