iPhone 3G, Previously JB on iOS 4.1 BaseBand 05.13.04 I've encountered an odd problem after jailbreaking using a custom IPSW 4.2.1 with preserved baseband 05:13:04. The phone was then unlocked using ultrasn0w 1.2.2 The JailBreak run perfectly and I haven't experienced any problems other than that explained below. I have installed apps, run a backup and transfered purchases to iTunes 10.2.1.1. Cydia is working fine (now Amazon have sorted themselves out) and all Cydia apps are installing without issue. It seems that Apple have locked out users from accessing MobileMe accounts via Jailbroken devices (specifically my iPhone/iOS/Baseband), although this obviously needs more investigation. When adding a new MobileMe account in Email I receive the following error. My best guess is that Apple are Validating the device by requesting a unique string created by combining the baseband and firmware. This theory is based on those two (firmware and baseband) being mismatched on my phone. I've only found a couple of posts on other forums about this issue and they were very recent (past month), so it seems that this may only affect users updating/restoring to 4.2.1 and preserving their baseband or updating it to 6.13(iPad). This is a very new discovery and I could be way of the mark with my theory but the symptoms of this problem have been experienced by others and seemingly there is no clear answer from those "in-the-know". If anyone has any suggestions please let me know. I'll be posting this up on other forums to spread my net was wide as possible.