Only works when your device isnt in deep sleep
To install custom roms on O4x:

1. upgrade to jb
2. root
3. unlock bootloader
4. flash custom recovery (cwm)
5. flash roms
6. if you encounter any issues, search, they've been answered already.

Got issues with RIL/IMEI/BASEBAND on custom 4.2, 4.3 or 4.4 ROMs on p880? Click me for possible solution!