I have an iPhone 3GS that I had jailbroken and unlocked on 4.3.3 and worked perfectly with this local carrier called Simple Mobile (which uses T-Mobile's GSM network). I just upgraded to iOS 5, jailbroke it and unlocked it and I lose my signal around 5 times a day. I get the Network Lost message and then "Searching" in the top left corner for about 3 minutes and then the phone finds the Simple Mobile network again. This happens even with a full signal in the area. Is anyone experiencing this problem after upgrading to iOS 5? Any suggestions?