I hope this is the right place to post this because I'm just really freaking out over my phone. So I have a 3gs with the old bootom and baseband thing. I wanted to upgrade it last night to 4.3.1. I looked up a couple guides and made sure I had everything right. First, I used redsn0w, but something went wrong, so I restored it. Then, I tried to use PwnageTool, but for some reason the ipsw file wouldn't open because of "wrong firmware bundle", even though I did everything in the directions. I was frustrated by now, so I decided to switch to my Windows computer and try out sn0wbreeze 2.4. Everything was going fine until I tried to update my phone to the customized ipsw. iTunes gave me an error of "Unable to restore (1600)" and another (1601) second time around. Now my phone is dead. It won't turn on no matter what I do. But iTunes still recognizes it when I plug it in. What does this mean? I hope someone can really help me out. I'm stressing like crazy over this.

Starting with redsn0w was a stupid way to begin if you rely on ultrasn0w to unlock the phone.

There are only failbreaks available for 4.3.1 at the moment, they are not recommended for the average user (especially if they rely on ultrasn0w to unlock)
sn0wbreeze is not recommended or supported here at hackint0sh.

Use TinyUmbrella to determine the current iPhone baseband and to check which baseband you have and what SHSH you have saved. If TinyUmbrella doesn't detect your phone, manually determinbe the ECID and create a manual entry in TinyUmbrella then try and save SHSH.

Reply with this information and we might be able to help you.