Untethered jailbreaking and carrier unlocking is now available for iOS 4.3.3, the unofficial iPhone Dev Team says. redsn0w and PwnageTool have been updated to support jailbreaking the firmware, which was released by Apple on May 4th. Unlocking requires ultrasn0w, and carefully avoiding certain pitfalls. Only certain iPhone 4, 3G and 3GS basebands are supported for example, and people must skip using redsn0w, turning instead to a custom IPSW file to update to iOS 4.3.3 while preserving a compatible baseband.
