I'm attempting to restore my jailbroken iPhone 4 (which is currently at 5.1.1) to stock 5.1.1.

I have SHSH blobs all the way back from 4.0 (including 5.1.1).

I've ran redsn0w and stitched my 5.1.1 shsh into the 5.1.1 ipsw downloaded from the net, however when I go into iTunes to restore with the image, it gets to "Preparing iPhone for restore...", grinds for about 5 minutes, then errors out with a 1604.

I've done some reading and people mention this is usually USB related.

I've tried different ports, different cables, completely different computers (Win7 and OSX) and they all have the same issue, 1604 error with the stitched IPSW.

If I try the stock 5.1.1 IPSW I get the usual error back because Apple isn't signing 5.1.1 anymore.

Any ideas? I'd like to restore this to fresh 5.1.1 since AT&T just factory unlocked it and I am going to sell it on eBay.