I looked around and found this(http://forum.xda-developers.com/show...php?p=49844276) read through and you will be enlightened
After you have downgraded your aboot, you will need a custom recovery. Download Flashify off the Google Play market (or use FreeGee to make the process faster) and place this file on your sdcard. twrp_184.108.40.206_loki-ls980.img
Open flashify, select recovery image, and find that .img, I have already loki'd this image, so you don't need to worry about it not working. Just be sure that you have downgraded your aboot first!
At the moment, the ZVA radio that came with your ota has completely broken compatability with all other non-ZVA ROMs, so if you want to install CM/PA/AOKP/DerpG2/OptimusDE, you will need to downgrade your radio to non-Spark ZV8/7, just flash this file in your newly installed recovery.
Now you're safe to flash any ROM!
so according to that you should be able to flash cm and others but then there is this note If you want to try the new radio (Spark), there's some things you need to be aware of, (when available) flashing youdug's stock ZVA ROM will NOT give you spark out of the box. You will need the new ZVA radio for this. You can find that here
You can only use twrp to install this radio. And it will ONLY work on ZVA ROMS. Do NOT install this radio over CM/PA, you will brick. and so I think you can't flash cm with zva
---------- Post added at 04:14 PM ---------- Previous post was at 04:11 PM ----------
ok did a little bit more reading the file you flash after installing twrp in that guide downgrades your radio to zv8 which means you can flash cm at that point as long as you don't update to the zva radio
"You DO NOT have to downgrade to the ZV8 radio now to run AOSP based ROMs. To run an AOSP based ROM with the ZVA radio you MUST flash Savoca's or dr87's kernel immediately after you flash the AOSP ROM."
So basically can we install cyanogenmod on a ZVA phone without downgrading ? Sorry If my question is stupid :/
Thanks for your help