Default [Q] What firmware is compatible with N900X?

I have N900X which has N9005DXUENE4 firmware installed (rooted + CWM). The problem is after KK update my phone loses network from time to time, and signal strength is weak compared to when it all worked fine on JB. Since there's no way to downgrade to JB, I was wondering what custom roms or other modem versions do you recommend that could possibly solve this issue?