Plx guyz let me know if there is a solution for this issue
Sent from my C6903 using xda app-developers app
If I am not wrong Baseband is a package with all the radio frequency needed for the phone to work properly. BTW, you can flash back the baseband for 4.3 in the same way.
Downloade the right 4.2.2 FTF, the one where bluetooth was working, and via Flashtool exclude everything except Baseband and flash it on 4.3. It will work, this was confirmed by users with weak radio signals.