Earlier last month Apple released iOS 5.0.1 firmware for iPhone, iPad and iPod touch. While it is possible to jailbreak this firmware tethered, the iPhone Dev Team had not updated the ultrasn0w unlock tool, meaning that it was not possible to unlock iOS 5.0.1. However a couple of hackers have developed ultrasn0w fixer which will unlock iOS 5.0.1 on iPhone 3GS and iPhone 4.
When iOS 5.0.1 firmware was released, all jailbreak tools were also updated so that it could be jailbroken. The iPhone Dev Team did not update the ultrasn0w software unlock tool, so those relying on a software unlock for their iPhone were told not to update to iOS 5.0.1. Carrier locked and factory unlocked iPhone owners didn't have to worry about any problems when updating to iOS 5.0.1. Its not like one can not do without iOS 5.0.1 update, it was merely a minor update that came with security and performance improvements as well as the fix for iPhone 4S battery issue, which failed to work nonetheless.
So in a nutshell, if you want to unlock iOS 5.0.1 on iPhone 3GS or iPhone 4 use ultrasn0w fixer, because Lord knows when the iPhone Dev Team will update ultrasn0w. Obviously, you need to jailbreak your device on this firmware first before you can unlock it. You'll only be able to use sn0wbreeze because its the only tool that supports unlockable baseband preservation on iOS 5.0.1. Follow our guide to learn how to preserve baseband and update with sn0wbreeze. The latest redsn0w can not preserve your baseband and hence there's no point updating to iOS 5.0.1 using it. Ultrasn0w fixer will unlock iOS 5.0.1 on iPhone 3GS or iPhone 4 that have the following unlockable basebands: 1.59.00, 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00.
How To Unlock iOS 5.0.1 Using Ultrasn0w Fixer:
Step 1: Launch Cydia. Tap on Manage followed by Sources.
Step 2: Tap on Edit followed by Add. Enter this URL: http://cydia.myrepospace.com/smolk/ and tap on Add Source.
Step 3: After the source is installed, tap on its name to enter it. There you'll find two different ultrasn0w fixer packages, one for iPhone 3GS and the other for iPhone 4. Install the relevant package and reboot your device after its done.
That's it. This is all you need to do in order to unlock iOS 5.0.1 on iPhone 3GS and iPhone 4. Ultrasn0w fixer will work perfectly fine, though many of you would consider waiting for the iPhone Dev Team to update ultrasn0w because its going to be much more stable, not to mention free of bugs. If you can't wait to update to iOS 5.0.1, here's your solution to unlock iOS 5.0.1.
Links:
Download iOS 5.0.1 firmware for iPhone, iPad and iPod touch
Download Sn0wbreeze 2.8b11 for iOS 5.0.1 baseband preservation and jailbreak