Running AOKP KK 4.4.2, I made a full backup of my system using CWM Recovery 6.0.4.7. I reinstalled stock ROM 4.2.2 10.3.1.A.2.67 to check for upgrades. (Sony removed all 4.3 upgrades for the C6506.
After that, I reflashed the boot.img, and restored my backup. On boot, the cell signal was "No...