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.
If you have an iPhone 4 with the older and unlockable 01.59.00 baseband, and you want to upgrade to the latest iOS 4.2.1 while preserving your baseband, we have a solution for you. The following method will allow you to upgrade your iPhone 4 to iOS 4.2.1, while preserving the 01.59.00 baseband which is unlockable using Utrasn0w 1.2.