I was reading over your posts over the past couple of days and I've been having this exact same issue. Each time I tried to reboot with redsn0w my phone would just vibrate/ring. Finally I just started over and that fixed the problem there. I had everything working/unlocked and running on T-Mobile. About 10 minutes after my phone randomly turned off and now I can't get it to turn on or do anything. I've tried restoring my custom .ipsw and rebooting and anything I can think of and the only thing I can get my phone to do is light up to that yellow/white screen that fades to black and different colors. I've been reading that iReb wil bypass that 1600 error in iTunes. I'm going to give that a try...