Good news for unlockers! A new version of Sn0wbreeze 2.3 is now available which supports Ultrasn0w unlock for iPhone 4 and 3GS users (old basebands only) running the latest iOS 4.3 firmware.

The following step by step instructions will help you jailbreak and unlock supported iPhone 4 and 3GS running on iOS 4.3. However before we proceed, please make note of the following:

• Sn0wbreeze 2.3b4 supports Ultrasn0w unlock for basebands (01.59.00 / 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00)
• Ultrasn0w is NOT compatible with the following basebands! (02.10.04 / 03.10.01 / 04.10.01 / 05.14.02 / 05.15.04)
• Upgrading your iPhone 3GS baseband to the 06.15.00 iPad baseband hack to unlock MAY cause you to lose your GPS!
• Sn0wbreeze is a tethered iOS 4.3 jailbreak for iPhone, iPad and iPod touch.

For iPhone 3GS Only: How to Update iPhone 3GS to 06.15.00 Baseband for Unlock:
Ultrasn0w 1.2 unlocking requires that your iPhone 3GS is jailbroken with 06.15.00 baseband. Follow the complete guide posted here (with PwnageTool) or here (for Redsn0w) to update your iPhone 3GS baseband to 06.15.00 and jailbreak it on iOS 4.1 / 4.2.1 before proceeding with the following steps.

Step 1: First up, you will have to jailbreak your iPhone 4 or 3GS using Sn0wbreeze 2.3b4. Instructions for jailbreaking iOS 4.3 using this new version of Sn0wbreeze are exactly similar to the last release. Simply download Sn0wbreeze 2.3b4 from here, and then follow our detailed step by step guide posted here to jailbreak iPhone 4, 3GS, iPod touch 4G / 3G and iPad running the latest iOS 4.3 firmware.

Step 2: Once you are done with the jailbreak, you can now unlock your iPhone on the supported basebands using Ultrasn0w 1.2 from Cydia. To do this:

• Start “Cydia” on your iPhone.

• Touch on “Manage” tab on the bottom.

• Now touch on “Sources” as seen in the screenshot below:
  

  
  
  
  jailbreaking  2011  tutorial  admin  sn0wbreeze 
  
  

  
  

• Touch on “Edit” and then on “Add”. You will be prompted to enter a url source as seen in the screenshot below. Type “http://repo666.ultrasn0w.com” and touch on“Add Source” to add this repo if you haven’t already.
  
  

Cydia will now automatically update your sources by following a series of automated steps.

• After installation is completed. Search for “ultrasn0w 1.2” in Cydia and install this application. This app will automatically unlock your iPhone so that you can use it with any carrier.
  
  

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

Keep in mind though that Ultrasn0w fix for iOS 4.3 is implemented in Sn0wbreeze 2.3 only. If you jailbreak your iPhone using PwnageTool on Mac then you wont be able to unlock it using Ultrasn0w.