Failing to restore my iPhone 4S from iCloud backup over wifi

I had the same problem. Tried for days to get it to work. On my 17th try, the restore completed. On that try, I was keeping the display active by tapping it every 40 seconds for around 2 hours and I had also turned off all encryption on my router. Not sure what caused it to work this time.

The weird thing is, the restore finished when the status bar said there were "about 3 hours" left in the restore. Seems like it miscalculated the size of my backup or something like that.

Apple really needs to figure this out.

I found that it fails unless the screen is on when it gets to 100%. Which is hard to ensure since the screen turns off after one minute when restoring from a backup :P

It seems if you only leave it for a few minutes it either keeps downloading, or pauses but is able to resume. If you leave it for longer it seems like power saving kicks in and the WiFi gets turned off...

I've spoken to several people on the phone at Apple, they are helpful but their only suggestion is tapping the screen to keep it awake. One guy got my hopes up saying if you turn 'Back to your Mac' on it will download the iCloud backups and let you restore, but when I pushed him on that, turns out it actually doesn't. Just lets you see them and buy more storage... (as well as the other Back to my Mac stuff).