Iphone 3g i got from At&t with firmware ( i'm not sure ) I jailbroke it, upgraded the firmware to (2.1.0 3G iPhone1,2_2.1_5F136_Restore.ipsw). Cancelled contract with AT&T took the iphone to Tmobile place. Smartass jailbroke it to 2.2.1 and handed it back to me with Tmobile service working. This is some 2 months back. Today i called up Tmobile regarding poor internet connection, losing EDGE often, hearing static while recieving calls. Rep tells me take out the SIM card and re-insert it. OK i opened the SIM card tray and there is a plastic thing between the SIM and the tray. The rep tells me this plastic thing is what is keeping my iphone unlocked and the reason for all my probs. I ask him how can i properly unlock it. He says Yellowstone. Sorry for the long story...but now i want to restore to 2.2.0 if possible. Can it be done. I tried and it would not restore to anything but 2.2.1. What to do guys ????