I had a 4.1 with 5.14.02, I checked and it said it can't be unlocked. Since I read that you can upgrade to an iPad baseband. I went to the redsn0w 0.9.6b5 and followed instructions. Restored to a 4.2.1. ran redsn0w, ticked Cydia, iPad baseband and battery percentage. Powered off phone. Put phone into DFU mode. After going into DFU mode i hit next and then redsn0w recognizes it and quickly closes. It doesn't bring me to the window that says "Finish." It just closes after i enter DFU mode and i click next. Phone stays in DFU mode. I gave it 15 minutes to let it do it's thing. I manually restarted iPhone using Power + Home button. Phone reboots, it's still on 4.2.1 and 05.15.04 baseband. Nothing changed. I had to manually activate phone with a spare ATT sim card. I'm trying to unlock it for tmobile.
It didn't fully jailbreak. Connect your device and rerun the redsn0w. Check the iPad baseband box and the install cydia box. Then try to re run the jailbreak