Okay, so I got an iphone off ebay that was unlocked for all carriers and jailbroken. It's an AT&T phone and I'm on tmobile. At first it was working fine until I connected it to itunes and made the mistake of updating to the latest software. I had no idea that it would mess with the jailbreak. First it went into connect to itunes/emergency call mode but i was able to unlock it again with an old at&t sim to get past that screen, but it's not working anymore. Now I've found out that the new software screws up jailbreak/unlock so I'm not really sure where to go from here. Is there anyway to downgrade the software or am I completely screwed?