For some reason my iPhone 4s (running on latest iOS 6 and never jailbroken) has crashed and is stuck on a rebooting loop. I tried to restore my iPhone from a backup I made about a week ago. iTunes prompted me to install the latest version (11.1) and I went ahead and did this, remembering that I saw somewhere that you need to be running the latest version of iTunes to be able to restore.
However, as soon as it picks up the iPhone in recovery and I press "Restore" it forces me to update to iOS 7. At this point I have pressed "cancel", as I'm concerned that if I go ahead and update, I won't be able to restore my phone with last weeks backup, because this was backed up under iOS 6.
How can I restore the phone to iOS 6 and recover my backup?