How to Unlock iPhone 4, 3GS on iOS 4.3 with Ultrasn0w & Sn0wbreeze 2.3b4

As iH8sn0w promised, he has just released Sn0wbreeze 2.3b4 which included ultrasn0w unlock fix for iPhone 4 and 3GS running the old basebands only on iOS 4.3. Let's check out the compatible & incompatible devices after the jump.

Which devices can be unlocked with Sn0wbreeze 2.3b4 ?

• iPhone 4 running 1.59.00 baseband ONLY.
• iPhone 3GS running 04.26.08, 05.11.07, 05.12.01, 05.13.04 and 06.15.00 basebands.

Incompatible basebands with Sn0wbreeze 2.3b4

• iPhone 4 running 02.10.04, 03.10.01 and 04.10.01 basebands.
• iPhone 3GS running 05.14.02 and 05.15.04 basebands (you can upgrade to iPad baseband 6.15.00 but this may cause you to lose your GPS, otherwise you have to wait for dev-team unlock of Gevey SIM unlock)

For iPhone 3GS only (how to update to 6.15.00 baseband): before you will be able to unlock you device on iOS 4.3 you have to update your iPhone 3GS to 6.15.00 baseband then jailbreak it on iOS 4.1 or 4.2.1, you can follow our guide posted here (Redsn0w) or posted here (PwnageTool).

Note: if you have already 6.15.00 baseband on your iPhone 3GS then bypass the above step.

Step 1: Now you have to jailbreak your iPhone 4, 3GS running iOS 4.3 using Sn0wbreeze 2.3b4 (Download link at the End), you can follow the video guide posted in forum.

Step 2: After you have finished your jailbreak, you can now unlock you iPhone 4, 3GS with Ultrasn0w 1.2 from Cydia. Follow the steps below:

• Press to launch Cydia Installer from your SpringBoard.
• Press to select the Manage tab at the bottom of the screen.
• Press to select the Sources button

• Now touch on Edit and then on Add. You will be prompted to enter the URL of the source. Type http://repo666.ultrasn0w.com and touch on Add Source to add this repository. 

• Once the source has been added press the large Return to Cydia button then select the Done button at the top right of the screen.
• Now select repo666.ultrasn0w.com from the sources list and at last select ultrasn0w from the list of packages as shown below then install this application.

Step 3: Now simply restart your iPhone, congratulations, now you have a fully unlocked iPhone 4 or 3GS, running iOS 4.3 !

Download Sn0wbreeze 2.3b4
Download iOS 4.3 for iPhone 4, 3GS