Those who might wanted to get a new flavor of Android 4.2.2. Jelly Bean on their LG Optimus G E975, you folks can now enjoy the goodies of CyanogenMod 10.1 Nightlies based with Android 4.2.2 Jelly bean tweaks. The installation only requires with already unlock bootloader and that also means that it’s already rooted with FreeGee unlock tool that now works in the international/european version of the LG Optimus G (LG-E975). This build has proven to work perfectly but it is up to you to discover everything.
Download and Install CM10.1 for LG Optimus G LG-E975
Download and Install CWM recovery at CWM site: http://download2.clockworkmod.com/recoveries/recovery-clockwork-touch-220.127.116.11-e975.img
CM10.1 nightlies are live at CyanogenMod Site: http://get.cm/?device=e975
GApps: Google apps
Warning: Installing custom ROM voids the warranty of your device, proceed at your own risk! we shall not take responsibility if some undesired outcomes may occurs onto your devices.
Put the CM10.1 ROM and the Gapps on your internal SDCard.
Reboot into recovery:
Select option “install zip from sdcard”
Then select “choose zip from sdcard”
Flash CM10.1 rom.
Flash Gapps package.
DO A FACTORY RESET
Reboot into system
That’s it! more info from +Ricardo Cerqueira