I have read in the past that there is no way to downgrade bootloader 6.02 but it has been a while since those original posts were answered. Does anyone know of a way this can be done? I have downgraded to 3.1.2 successfully and I have jailbroken successfully, but I can't pick up T-Mobile's signal using any know unlocking system. It just keeps searching or says no service. I have tried every program I can find but nothing works. Can anyone please help?