Hi all. My iphone does not work with 2G signal now. My sim card is 3G. When my firmware was 2.1, I used turbosim with my 3G sim card. My phone worked good and it could search/use 2G signal. Now, my upgrade firmware to 2.2 and use yellowsn0w 0.96. Something happened. When I put my 3G sim card in iphone, I need to turn on "3G" and it can get 3G signal and works good. But if I turn off "3G", my phone can not get any 2G base station signal and appears "no service" finally. Therefore, I borrowed a 2G sim card to try it. It can get good signal but I can not make/receive calls with iphone. Does anyone has same situation with me? Thank you.