iPhone Dev team just released Ultrasn0w 1.2 unlock for iPhone 3G an 3GS. Latest release of Ultrsn0w supports baseband 04.26.08, 05.11.07, 05.12.01, 05.13.04 and now 06.15.00. Strange but true iOS 4.1 baseband 05.14.02 and iOS 4.2 .1 baseband 05.15.04 are not supported with Ultrsn0w 1.2 But if you are stuck on Baseband 05.14.02 or 05.15.04 you can update your baseband to 06.15.00 and enjoy the Ultrasn0w unlock.
This time the procedure is very different, first you have to upgrade the baseband of the iPhone with the iPad 3.2.2 firmware and then you can unlock the phone with Ultrasn0w part, through Cydia. Following are the guides to update your baseband to 06.15.00
- Upgrade iPhone 3G, 3GS Baseband 06.15.00 with PwnageTool Unlock Edition (Mac)
- Guide to Update Baseband 06.15.00 With Redsn0w (Windows and Mac)
- Unlock iPhone 3G, 3GS Baseband 05.14.02 or 05.15.04 with Ultrasn0w
Theory : iPhone 3G/3GS baseband is same to iPad 3G. Apple blocked AT+XAPP hole with baseband 5.14.02 and 05.15.04 but the hole is still vulnerable with iPad 3G iOS 3.2.2 baseband 06.15.00 and the theory is to update your baseband to 06.15.00 and use the latest ultrasn0w to unlock.
Drawbacks : There are obvious drawbacks to this unlock method. Update the baseband to 06.15.00 is irreversible. Furthermore, it is not possible to update to future versions of the baseband, unless a higher version number than 06.15.00 This also means that you can expect problems if you try to update to official firmware versions from 4.2.1 IOS.
Warning : Certainly don’t update to 06.15 if you don’t need to! Only do this if you need the unlock and you’re stuck on 05.14 or 05.15, and you’re willing to assume the above risks.