The iPhone Dev Team has released UltraSn0w 1.2.2 update to unlock iPhone4, 3GS running over iOS 4.3.2 firmware.
UltraSn0w 1.2.2 supports iPhone 4 1.59.00, and iPhone 3GS with 04.26.08, 05.11..07, 05.12.01, 05.13.04 and 06.15.00 baseband.
UltraSn0w 1.2.2 does not support new basebands including 2.10.04, 3.10.01, and 4.10.01.
Note: iPhone 3GS users can upgrade their device to iPad baseband 06.15.00 which is unlockable but your device may lost GPS feature after the unlock process.
Requirement: Your iPhone with iOS 4.3.2 must be jailbroken to proceed for unlock, if that is not then follow our guides below to jailbreak iOS 4.3.2 first.
Jailbreak iOS 4.3.2 untethered with RedSn0w 0.9.6rc14, jailbreak iOS 4.3.2 with PwnageTool 4.3.2.
Unlock iPhone 4, 3GS over iOS 4.3.2 with UltraSn0w
Step-1
Open Cydia and tap on Manage tab
Step-2
Tap Sources > Edit > Add
Step-3
Type this URL there http://repo666.ultrasn0w.com and tap Add Source button and let Cydia complete the process
Step-4
Tap on Search tab and search for ultrasn0w and install it on your iDevice and the installation process will unlock your iPhone with the above supported basebands
Step-5
Reboot your iPhone and that’s it
Enjoy, your iPhone 4, 3GS over iOS 4.3.2 is unlocked now and free to use SIM of any carrier of your choice.