Downgrading from iOS 7 to a recent full backup of iOS 6.1.3 [duplicate]

Note: this will only work if downgrading from a prerelease beta OS to a regular version.

You can only ever restore an iOS device to the latest public version.

Downgrading is super easy: Just put your iPhone into DFU mode (plug into iTunes, power off, hold down Sleep/Wake and Home button for 8 seconds, let go of the power button and continue to hold down the home button until iTunes alerts you. The screen should be black) and follow iTunes through there.

Don't quote me on this, but I believe there's a download list of ISPWs for iOS 6.1.3 on the home page of the iOS Dev Center. You should be able to download an image and reload your device the same way you loaded it with the beta image. I believe the 6.1.3 images listed here are still being signed (by Apple).

If you can successfully get your device running a clean install of 6.1.3, you should be able to do a restore from there.

First of all

Apple’s official word is that you cannot downgrade your device to iOS 6 after installing the beta. This means you shouldn’t install iOS 7 unless you are happy running buggy software for a few months.

To try to downgrade users must first download the IPSW for their device (from here).

Then connect the device to a Mac or PC with iTunes open. Next press hold the Home and Sleep/Wake button simultaneously for 10 seconds and then release the Sleep/Wake button until iTunes detects your iPhone has been put into recovery mode. While this happens, your iPhone’s screen will remain black.

With the device still connected, in iTunes Option+Click (Mac) or Shift+Click (Windows) the Restore iPhone… button. A window should open, in it locate the iOS 6 IPSW you downloaded, select it and confirm your selection. iTunes will now attempt to downgrade your device, after which point you can restore from local or iCloud backups.