Here is another short tutorial for unlocking the iPhone 3GS 4.3.1 with Ultrasn0w 1.2.1 for the iOS 4.3.1.Please keep in mind that this not a new unlock but just a compatibility fix for the iOS 4.3.1 so that those who have been following baseband can unlock their device on the iOS 4.3.1.
Please make a note of the following supported iPhone 3GS basebands :
Please do not upgrade to iOS 4.3.1 without preserving the basbenad. Use the PwnageTool 4.3 or Sn0wbreeze 2.5 to jailbreak the iOS 4.3.1 in untethered mode with the preserve baseband option.
Now here are the unlock instructions :
Step 1 :
Jailbreak the iOS 4.3.1 on the iPhone 3GS with PwnageTool 4.3
Jailbreak the iOS 4.3.1 on the iPhone 3GS with Sn0wbreeze 2.5
Step 2 :
Start Cydia from the springboard.
Step 3 :
Now you should be able to see two options, Packages and Source.
Step 4 :
Navigate to Packages -> Edit -> Add and then enter the following :
repo666.ultrasn0w.com as the repository URL (ultrasn0w has a zero and not an o).
Step 5 :
Now go back to the Sources menu under Cydia and you will see the Ultrasn0w package.
Step 6 :
Click on the Ultrasn0w package and then select Ultrasn0w 1.2.1.
Step 7 :
Tap the Install button and let Ultrasn0w 1.2.1 finish up with the installation procedure.
Step 8 :
Your iPhone 3GS will reboot now and get unlocked on the iOS 4.3.1.
Happy jailbreaking once again… !!!