Seems to be failing for me, redsn0w runs for about 15 minutes in the step where the phone says downloading jailbreak data. After that the phone reboots and goes to the password screen, and redsn0w is still in the uploading ramdisk screen. Nothing happens after this, no Cydia. Thoughts on why it failed? Phone is on a custom (devteam update#3) 4.2.1 ipsw with baseband 5.13.04, restored all user settings no problem and everything works great. Was previously 4.0.2.