Hello, on my family me and my mom have this phone called [h=3]Samsung I9070 Galaxy S Advance[/h] I have a signal drop problem during calls, while i am talking after some minutes or so from 2 or 3 signal bars the signal goes down to 0 and cannot hear the other at all and in some cases it even hangs up. Tried switching phones and the same thing happens, tried upgrading to latest official firmware (4 Jellybean) and still nothing, well i am suspecting it to be a SIM card problem for some reason but i can also say that it could be a device issue, maybe the advance series is problematic. What do you think?