I am attempting to update my jailbroken iPhone 4S from 5.0.1 to 5.1.1. If I click the Restore button, I get error 1604. If I shift-click on the Restore button (then use iPhone4,1_5.1.1_9B206_Restore), I get error 1603. I have: Ensured I am running the latest version of iTunes Restarted my PC (Windows 7 x64) Tried to use a different USB port Restarted the Apple Mobile Device service Reset the iPhone sync history in iTunes Booted into DFU mode before trying update Also, sometimes I get error 21. Any ideas?