Hello guys. I've had this problem with my iphone 3gs, I had the version 4.0 and couldn't update to 4.3.3 (latest version). So I downloaded the 4.3 ipsw file from a site and it wouldn't work either (with shift-restore and shift-update). Then I did the same for 4.1 and it worked. So now I have the 4.1 version and it won't let me update to the 4.3 or 4.3.3. I have updated both itunes and my windows 7 and it won't work!