As we wrote yesterday the Dev-Team released Redsn0w 0.9.7b1, and just few minutes ago they released the beta 2 version of the same. The new version has some major fixes. The previous beta edition had some major errors and crashes while using iTunes, Bluetooth and the music getting stuck.
Redsn0w 0.9.7b2 allows to convert tethered jailbreak of iOS 4.2.1 to untethered on iOS devices. Still the second beta of Redsn0w 0.9.7 is only for testing.