Folowing Ricardo's post on Google + announcing the official CM10.1 for E975, I said give it a try.
I had installed the ClockworkMod from the Play Store (the premium version), I flashed the CWM touch recovery for E975 (in app payment), booted in recovery and installed the official CM10.1 zip.
Rebooted and... bootloop!
The Cyanogenmod logo was spinning but it would not start.
So I got my first softbrick with E975.
I had to reflash the official kzd, reroot, unlock bootloader.
For now I will stay with the official 4.1.2 stock ROM.
I hope that CM10.1 will work with the TWRP and then I'll give it a try.
Did you do a factory reset from recovery? This step is very important otherwise you end with a bootloop. So you just had to reboot in recovery and wipe data or do factory reset and reboot.
The ROM is working 100%. Fully working 13 megapixel camera and very smooth.
The easiest way is:
Use FreeGee from Play Store and free your device (void your warranty)
Download RomManger from Play store and flash CWM recovery. Not TWRP !!!
Put the ROM on your Internal storage Download here:
http://get.cm/?device=e975
Put Gapps for jb 4.2.2 (20120301) on internal storage Download here:
http://goo.im/gapps
Reboot to recovery (Keep Volume up while rebooting and press the Volume down rocker two times and press Power button)
Select option “install zip from sdcard”
Then select “choose zip from sdcard”
Flash CM10.1 rom.
Flash Gapps package.
Go back to main screen in recovery
Important step !!! - Select FACTORY RESET in Recovery and press Power button - !!!
Reboot into system
Enjoy CM 10.1 on your LG OG E975