Though the iPhone Dev-Team hasn’t yet added support for the iPhone 4 and iPhone 3GS (under iOS 5.1.1) to its ultrasn0w unlock tool, that doesn’t mean jailbreakers can’t apply a carrier unlock to their beloved handset. Thanks to the recently released “ultrasn0w fixer for 5.1.1,” users can tweak the ultrasn0w package, making it compatible with the latest iteration of Apple’s mobile operating system running on an iPhone 4 or iPhone 3GS handset.

Here’s how to unlock your iOS 5.1.1-powered iPhone 4 or iPhone 3GS using ultrasn0w fixer:

First – make sure your iPhone’s baseband is supported by the software. Compatible basebands include:

  • 01.59.00
  • 04.26.08
  • 05.11.07
  • 05.13.01
  • 05.12.01
  • 06.15.00

If your iPhone’s baseband is listed above, you should be good to go.

Second – install ultrasn0w fixer for 5.1.1. In the Cydia app, head over to “Manage,” and then “Sources.” Here, add the following repository to your list of sources: http://repo.iparelhos.com. Next, a quick search in the application (after the source has added) should reveal ultrasn0w fixer for 5.1.1 – download this package (it’s available for free).

Third – once ultrasn0w fixer for 5.1.1 has downloaded, download version 1.2.5 of ultrasn0w, which you can find by performing a quick search in the Cydia application.

That’s all there is to it! If you’ve followed the above instructions (specifically, be sure to have installed the fixer before installing ultrasn0w), and your iPhone 4 or iPhone 3GS’s baseband is listed above, once installing ultrasn0w 1.2.5 your iOS 5.1.1-powered iPhone should be carrier unlocked.

Enjoy!

[Thanks Jailbreak Untethered for the tip!]