Did the problem go away when you switched SIMs? The only reason I think its a problem related to my firmware flash is that I didn't have this problem prior to the upgrade. I'm really upset with myself for doing the upgrade. I ride elevators up an down frequently during the day. I almost always lose signal inside them. I used to be able to pull signal back almost immediately after exiting the elevator. Now, I always get the Network Registration error. I'm going to see if this lasts for another couple days. If so, iUnlock, the people that flashed my phone, said they will try a phone reformat to rebuild the directory structure. Whatever that means. I hope it works.