Here is a good news for all those of you who are waiting for iOS 4.2.1 unlock. MuscleNerd, the member of iPhone Dev team replies to one of his many followers on twitter that Ultrasn0w unlock for iOS 4.2.1 running on iPhone 3GS and 3G might be released this week.
hiemanshu: @MuscleNerd any ETA on unlock or should I say unl0ck
MuscleNerd: @hiemanshu now that redsn0w is out, can focus back on the unlock. The 3G/3GS version should be out this week. i4 will be longer.
iPhone 4 users, will have to wait little longer to get the working version of Ultrasnow to unlock iPhone 4 on iOS 4.2.1 and due to change in baseband, the existing version of Ultrasn0w also doesn’t work on iOS 4.1 and above.