A while back we broke the story of a bug which was allowing restores to iOS 9 firmwares, without even needing a jailbreak. It was subsequently discovered that the bug was more far-reaching than originally thought, allowing restores to iOS 9.x from any firmware, not just from iOS 9.
The tool was released a week or so ago, and so we thought the time was right for a tutorial. Follow our instructions here to bring any 32-bit device back to any iOS 9.x firmware you have blobs for, from any starting firmware. No keys, bundles, nonces, or jailbreak required!