The developer behind the Sn0wbreeze jailbreak tool, ih8sn0w has released Sn0wbreeze 2.2 version for untethered jailbreak of iOS 4.2.1 on Windows. Similar to the PwnageTool 2.2, which was released earlier for the same purpose, Sn0wbreeze 2.2 is also using the same exploit used in the GreenPois0n tool released by Dev Team.

Download SnOwbreeze 2.2

Like the PwnageTool for Mac, SnOwbreeze 2.2 preserves the baseband while updating to the custom made jailbroken iOS 4.2.1 firmware so that you could unlock your iPhone using Ultrasn0w 1.2.

Download SnOwbreeze 2.2 from here