iPhone Dev Team member MuscleNerd, just a little ago had confirmed that the untethered jailbreak for iOS 4.2.1 on Mac OS X will be releasing in the Christmas weekend. Two minutes later, he again replied to a question asking, when the untethered iOS 4.2.1 Jailbreak tool for Windows will be released. His reply was that, if all the Mac Testers give good feedback to the new jailbreak method, they will port it to Windows very soon!

Below are the tweets of MuscleNerd :

Untethered iOS 4.2.1 Jailbreak

This was his second tweet :

Untethered iOS 4.2.1 Jailbreak

Stay Tuned to Tips Needed for more updates on the topic!