this is an old thread...but fwiw the only solution for me was to flash the complete stock att ma4 4.1.2 rom ...and then work back up to whichever rom of choice.
this was after trying multiple bootloaders, kernels, modems, recoveries, roms...4.3, 4.4, etc.etc...
i did find another flashing combo that seemed to fix things but after a period of time wifi/bluetooth would randomly disappear again(!) and i'd have to repeat the whole process over again. strange.