Today iPhone Dev Team has released Ultrasnow 1.2.3 for unlocking iOS 4.3.3 on iPhone 4 and iPhone 3GS. Ultrasn0w 1.2.3 does not include any new baseband support but it unlocks those devices which are currently on unlockable baebands.
The current version of Ultrasn0w can unlock the following basebands:
Ultrasnow 1.2.3 doesn’t support the following basebands:
So, if you are still on unlockable baseband, you can restore your iPhone 4/3GS with custom iOS 4.3.3 and then unlock with this updated Ultrasn0w. There are two tools available to build custom iOS .iPSW file. One is PwnageTool which runs on OS X only and another is Sn0wbreeze which is compatible with Windows operating systems. These tools not only preserve the baseband to retain the existing unlock but also jailbreak iOS 4.3.2 (untethered). They can also be used to add custom animations (like bootlogo), to add pre-installed Cydia packages and sources and to hacktivate the device.
Here is the step by step guide to unlock iOS 4.3.2 using Sn0wbreeze 1.2.2.
Step 1: Backup your device using latest version of iTunes before starting the actual process.
Step 3: Once your device is jailbroken, connect it with internet using a WiFi connection.
Step 4: Launch Cydia from your device Springboard.
Step 5: Tap on Changes and then on “Refresh “.
Step 6: After the changes are refreshed, use the Search option and type Ultrasn0w to search and install it.
Step 7: Restart iPhone after installing Ultrasn0w and you will see the carrier name and signal bars in the top left corner.