If you try to DFU restore an iPhone X to the latest version of iOS (11.1.1), you'll get an error saying that FaceID isn't available and to try setting it up later. The front facing camera works fine, but a hard reset won't fix the issue. Apple will just swap the device for a new phone. You can fix by downloading the 11.1 IPSW and restoring from that while it's still signed.
Just putting it out there for anyone who's googling the issue.
Just putting it out there for anyone who's googling the issue.