You will still need an unlockable baseband to utilize ultrasn0w, but if you meet the requirements, it is now possible to unlock your iPhone 4 or iPhone 3GS running iOS 5.0.1…
You will need a jailbroken device to utilize UltraSn0w 1.2.5. Your baseband must also meet the following requirements:
iPhone 4: baseband 01.59.00
iPhone 3GS: basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04, 06.15.00
If you’re interested in preserving your baseband for the latest Apple firmware upgrade, you can follow our baseband preservation tutorial.
This version of UltraSn0w doesn’t bring any new baseband compatibility to the table, and it only works with the iPhone 4 and 3GS. No iPhone 4S support just yet, but there are rumblings that support could be coming for those devices in the future.
Are you running an unlocked iPhone using UltraSn0w?