By following the steps below, you can run the new 4.4.2 kitkat rom from LG (and 4.4.2 stock modified roms to come) with our old partitions which are fully loki-able
DO THIS ENTIRE PROCESS AT YOUR OWN RISK - IF YOU DO NOT UNDERSTAND THESE DIRECTIONS, THEY ARE NOT FOR YOU. I TRIED TO MAKE THEM AS SIMPLE AS POSSIBLE. THIS WILL WIPE YOUR WHOLE PHONE. THIS IS FOR D801 ONLY.
Also please no stupid questions, I will not answer. I will try to help with legitimate problems.
If you upgraded to 4.4.2 through the KDZ or flashed the 4.4.2 stock rom from smiley on this forum (since he included the new partitions) you must follow every step here. If you are still on 4.2.2 partitions (You have these if you currently are using an aosp / cm rom with a custom recovery) - Then you may go straight to step 5.
1. You must revert to stock 4.2.2 using this guide. You must restore to the C version. DO NOT USE G. You can find the link to 801C here.
2. Once you successfully flash this, your phone should boot loop on the T-Mobile screen. Boot into recovery (which is now LG's stock recovery) once you are in press power twice to data reset. Remove the USB cable from the phone when trying to boot to recovery, it makes it much easier for some reason. After data reset your phone should now boot into stock LG 4.2.2
3. Root your phone with this.
4. Install a custom recovery with this guide. The TWRP listed in this guide is old and you must this one instead. Method 1 works fine for this if anyone is wondering.
5. At this point you should have 4.2.2 partitions with root and custom recovery. Bet you wish you didn't update to 4.4.2 Stock at this point
6. Boot into recovery. FULL WIPE EVERYTHING (Except for internal storage. This mean you wipe System Data Cache and Dalvik. Very Important.) Flash this Rom in recovery that I put together (And here is a Mirror). It contains the 4.4.2 KDZ system image with the 4.4.2 modem. Make sure you backup your EFS. The kernel inside this rom is stock LG 4.4.2 with a minor change to allow it to boot on the 4.2.2 bootloader. Thanks to the dev's in that thread who worked on it.
7. Flash SuperSU for root.
8. You are now on 4.4.2 Stock rom with recovery, root, loki and the ability to flash custom 4.4.2 stock kernels when they are released (soon)
At this point you will be able to flash any rom you want, including aosp stuff. Do not flash any other kernel on the included LG 4.4.2 stock rom. I will be making a custom kernel / 4.4 stock roms for this soon anyway - WHEN FLASHING 4.4.2 STOCK ROMS PLEASE MAKE SURE THEY DONT HAVE PARTITIONS BESIDES SYSTEM/MODEM/RPM/TZ INSIDE!!!! JUST OPEN THE ZIP AND CHECK INSIDE. ANYTHING EXTRA YOU WILL HAVE TO REDO THIS ENTIRE PROCESS !!!!!!!! I really hope devs stop putting up roms with the new partitions included.