It looks like the Chronic Dev Team has confirmed an untethered jailbreak for iOS 4.2.1. This comes as great news to many current-generation iOS device owners who are waiting patiently for an untethered jailbreak that does not require saved SHSH blobs and the ISPW file for iOS 4.2 beta 3, the latter of which is only available to developers. They've just a released a video showing off an iPhone 4 restarting, and then launching Cydia.