Was on the GM but wanted to go to the public version of iOS 8. By putting my iPhone into DFU mode and "restoring" it to the public version of iOS 8, I gained about 3 GB after completing the restore from my backup I made just prior to the restore. I didn't lose any pictures or apps or anything like that. What could have been erased then? I seriously searched all over my iPhone trying to figure it out but everything is just like it was before.