As promised on Twitter a few days ago, the Dev Team released a beta of Redsn0w for Mac to provide an untethered jailbreak solution for iOS 4.2.1. Redsn0w 0.9.7b1 should allow you to jailbreak your iPhone 4, iPad and iPod touch 4th gen without having to plug your device in your computer on each reboot or shutdown. iPhone 3G, old-bootrom iPod touch 2nd gen and iPhone 3GS owners don’t need this new Redsn0w as they already have an untethered jailbreak.
This beta version of Redsn0w (or as the Dev Team calls it, the “backup plan”) is meant for testers willing to provide useful feedback on this new jailbreak. To use it, you’ll need iOS 4.2 beta 3 hashes saved on Cydia and the iOS 4.2 beta 2 IPSW file saved on your computer. In this beta the bluetooth functionality is disabled, the task switcher will make the Springboard crash and the iPod player is only enabled on the iPod touch 4th gen.
Redsn0w 0.9.7b1 is available here.