I have recently purchased an unlocked and jailbroken iPhone for T-mobile with the 3.0 software. Unfortunately, after a months use I went to sync the iPhone to my computer and clicked to update the phone without thinking of the consequences. After installation, the phone was returned to its original software and required an AT&T sim card, as my T-Mobile sim was not recognized due to the software update and reboot. Therefore, I was required to re-unlock the phone and now I am stuck with the 2.2.1 software. So my real question is... Is there any way I can update my phone's software with an AT&T sim card and then insert my T-Mobile card without having to re-unlock the phone??? Or is there another method that isn't too complicated? Thanks in advance.