MuscleNerd, a member of the Dev-Team, recently tweeted that they have untethered the jailbreak for iOS 4.2.1. The jailbreak will cover all devices. There is no info about a release date but we will keep our eyes open! I can’t wait! Below is a demo video and what MuscleNerd has to say about it.
Got “backup plan” for untethered 4.2.1 JB working (video coming up). Uses mysterious 4.2b3 hashes Cydia kept for you. (It’s a “backup plan” because comex is working on a more extensible one, but this method is also generalizable)