Memeber of the iPhone Dev-Team, @MuscleNerd has just made an official announcement that the upcoming update of ultrasn0w unlock for iPhone 4, iPhone 3GS is now fully working on iOS 4.2.1. He tweeted the following:
Finally got ultrasn0w working fully on 4.2.1. Apple inadvertently(!) broke ultrasn0w via aggressive compiler optimization
Earlier, @MuscleNerd had also given the ETA for the release of ultrasn0w unlock update. He said that it should be available by Sunday for the iPhone 3G and iPhone 3GS. While, the unlock for the iPhone 4 might take a little more time.
Stay tuned to our website and we’ll let you know the moment it gets available!