How do I use a downloaded restore file to restore my iPhone

Developer updates are handled in the same manner as public ones. Apple does make an .ipsw file available on their site and they are pretty easy to find on many sites.

Hi Jesusboy4ever,

I see the problem you are having. To restore from a .ipsw file, If you are on windows hold shift when clicking restore. If you are on a Mac, hold option while clicking restore