Reliablility problem in current git?

Hi, I have a git clone from 23.01.2012 and a current git clone. When I compile both and use the mobile appliation, I have a strange problem in the current code. Very often I can't send USSD codes (and maybe also can't communicate in other ways; USSD is the costless way to check whether I am connected or not). Ok, this is what I do: I send "service 1 *#21#", wait the answer and the string "% On Network, normal service: Germany, O2". Then send it again and so on. With the old code, I reliable get the answer e.g. "% Status: deactivated". With the new code, I very often (sometime already when trying first time) get nothing back and after some seconds only "% Service connection terminated.". Can someone confirm this behavior? Thanks Tim