Update : Ultrasn0w 1.2.4 has been released for more details - Click Here
Unlock iPhone 4 and iPhone 3GS on iOS 5 with Ultrasn0w coming tomorrow. MusclNerd of iPhone Dev-team has confirmed today that ultrasn0w unlock will come tomorrow to unlock iPhone 4 and iPhone 3GS on iOS 5.
will coordinate ultrasn0w iOS5 compatibility update to come out *after* a planned MobileSubstrate update tomorrowUltrasn0w will be fixed on iOS 5 to unlock the already unlockable basebands on iPhone 4 and iPhone 3GS.
Unlock iPhone 4, 3GS iOS 5 with Ultrasn0w - Supported Basebands :01.59.00 / 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00
So that any other baseband won't be under the upcoming ultrasn0w umbrella. To unlock iPhone 4, 3GS on iOS 5 you will need to jailbreak them via custom firmware with Redsn0w or sn0wbreeze to preserve the above unlockable baseband. As usual we will prepare full step by step guide to let you know how to unlock iPhone 4, 3GS on iOS 5 with ultrasn0w, Stay tuned.
Update: Now you can make iPhone official factory unlock, you can check the details from here