Ultrasn0w 1.2 was released by dev team on 29th November 2010 to unlock iOS 4.2.1
Please note, that the basebands: 05.14.02 (ios 4.1) and 05.15.04 (ios 4.2.1) are not supported by this release of ultrasn0w, but there is work around for this issue in this release.
Work around for basebands 05.14.02 and 05.15.04 is to upgrade it to 06.15.00 and then unlock using ultrasn0w 1.2.
To unlock 05.14.02 and 05.15.04 basebands, first we have to upgrade our iPhone with the iPad 3.2.2 firmware which have baseband 06.15.00. Once the iOS is upgraded by the iPad 3.2.2 firmware, we can unlock this firmware with ultrasn0w 1.2 through cydia.
To use ultrasn0w 1.2 to unlock your iPhone, you need to follow these steps:
- Upgrade iPhone to baseband 06.15.00 with PwnageTool Unlock Edition
- Update iPhone to baseband 06.15.00 with Redsn0w
- Unlock iPhone 3G, 3GS baseband 05.14.02 or 05.15.04 updated to iPad iOS 3.2.2 firmware 06.15.00 with ultrasn0w 1.2
How it works:
iPhone 3G,3GS and iPad 3G baseband are same. Apple blocked AT+XAPP hole in baseband 05.14.02 and 05.15.04 but the hole is still vulnerable with the iOS 3.2.2 of iPad 3G with baseband 06.15.00.
So if we update the baseband of your iPhone to 06.15.00 it will be unlocked by the latest ultrasn0w version 1.2.
Drawbacks:
This unlock method is different from the previous ones and definitely not as safe as them. This method updates your baseband to 06.15.00 which means that it will not be possible to update to future versions of baseband unless a version higher than 06.15.00 is released.
Note:
Do not update your baseband to 06.15.00 if your iPhone is already unlocked with earlier version of baseband. Only upgrade if you are stuck on baseband 05.14.02 or 05.15.04 and also understand the above mentioned risks involved in the process.