I am using an unlocked ATT Note 2 on T-Mobile. I have great 4G! Coverage and Wifi works but the cellular signal hangs at one bar to 0 bars often going into emergency call only mode. After a while the signal will go back up to on or two bars and I get service again. What control's the cell phone signal (is it just an antenna or is it software based). I have flashed the original modem, the second upgraded modem and now I am on M6. The signal continues to do the excat same thing through each flash. I have tried different ROMS and the same thing occurs. I did not slight decrease in the jumps to "emergency call only" mode after upgrading to MK6. Are the an other things that I could try or should I have the internal antenna looked at?