For the iOS unfaithful out there that simply have to go against Apple and unlock their iPhone, the iPhone Dev Team has released an updated version of Ultrasn0w to unlock iPhone 4.3.1 on the 3GS and iPhone 4 with basebands 01.59.00, 04.26.08, 05.11.07, 05.12.01, 05.13.04, and 06.15.00 only.

Thus the guys over at iPhone Download Blog have come up with a guide for unlocking your iPhone 3GS and iPhone 4 running iOS 4.3.1 as long as the device runs one of the above basebands, and say that if not then there isn’t a solution available just yet.

So we thought we’d pass the guide along, which is a three-step guide, so lets get to it…First off you’ll need to jailbreak and update your iOS device using either updating to iOS 4.3.1 via PwnageTool or updating to iOS 4.3.1 and preserving baseband 01.59.00 via TinyUmbrella.

Next you launch Cydia, then go to “Manage > Sources > Edit > Add” then type in http://repo666.ultrasn0w.com, and this should install the Ultrasn0w unlock, once Ultrasn0w is installed reboot, after which you can insert a different SIM card, although if you are using T-Mobile you will need to disable 3G in settings.

And that’s it the job is all done and should take just a few minutes to accomplish, so if any of our readers give it a bash feel free to let us know if you experience any problems or if all goes smoothly.