Those who have updated their iPhone 4 / 3GS to the latest iOS 4.3.2 and jailbroken using tools like latest sn0wbreeze or PwnageTool custom bundles must find out that even after preserving their baseband, they aren’t able to get Ultrasn0w 1.2 working to unlock their devices. However, if your device has either of these basebands 01.59.00 / 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00 and you are running iOS 4.3.2, DJayB6 has come up with a tool called Ultrasn0w Fixer to help you out.
Here is how you can install Ultrasn0w Fixer to unlock iOS 4.3.2 on iPhone 3GS / iPhone 4:
** You have to install the Ultrasn0w Fixer before you put ultrasn0w 1.2 in iOS 4.3.2.
Open up Cydia and go to Manage > Sources > Add then enter the following repo:
Now browse the repository added and install Ultrasn0w fixer from it. You can also search for it in Cydia once the repo has been added.
Once done, it will automatically install ultrasn0w 1.2. Now you can unlock iOS 4.3.2 on your iPhone 3GS / 4 using ultrasn0w.