The iPhone Dev Team has announced a new, untethered jailbreak for iOS devices running 4.2.1, including the iPod touch 4G, iPhone 4, iPhone 3GS and iPad. The new system takes advantage of the 4.2b3 hashes backed up by Cydia, and is being described as a "backup plan" by team member MuscleNerd, since comex is currently working on "a more extensible" alternative method.
Video demo after the cut
This untethered jailbreak does have its advantages, however: it wastes no current exploits, and could be leveraged against future jailbreaks on newer firmware releases. No news on when we might see it released, however, but you can watch the hack in action in the video below.