Alright so.. I had 3.0 beta 2 (registered dev) and i got kinda sick of the bugs and stuff so i decided to go back. Everytime i put the iPhone in DFU mode and then restored to the 2.2.1 file, i expected the 10XX errors that everyone else was getting, but i continued to get the 1600 error! THIS IS FOR THOSE WHO HAVE TRIED EVERYTHING, and still can't get the CORRECT error in iTunes So this is how i ended up doing it, and it worked I have a fully functional 2.2.1 iPhone 3G. (Used a combo of Mac & PC) 1. DO NOT DFU MODE your iPhone. Simply connect your iPhone to your mac, and OPTION+CLICK on "Restore". Then scroll to the 2.2.1 ipsw file on your harddrive and let iTunes do what it does. 2. About half way through, iTunes stopped and gave me an error which i believe was (21), i got scared but actually i was able to continue. My iPhone had the connect to itunes thing, and i thought the best thing to do was to just restore and go back to 3.0, i didn't wanna mess up my phone. 3. I think option-restored again and tried to put 3.0 back on (scroll to your 3.0 ipsw file and click restore). Half way through this restore, i got the 1013 error! This means 2.2.1 was already installed on my phone. SWEET. 4. So now i just had to bump it out of DFU mode, so i opened up Quickpwn on WINDOWS, did what it directed (hold the home/power buttons for 15 seconds and let go of the home for 2 seconds) and boom, i had 2.2.1 I then brought it back to my mac were i restored from a previous 2.2.1 backup, and now all is well and bug free Obviously, i'm not sure if this will work for everyone, but it worked for me and one of my twitter followers that guided me through it. Good luck!