Join the rest of a lot of people, I have been trying to fix my sister in laws ne Xmas Pressy.... Gave up, have been trying to follow the internet help.. But gave up.. she has now taken bake to the Phone Carrier.
I finally found a solution for my problem. I downloaded a new .IPSW file and put my iPhone into DFU mode then restored through iTunes using the new file. Worked perfectly twice.