I made a mistake and I think there was a download before I corrected it. So whoever downloaded this look out: I had written IXUS 800 IS 100D and had files named accordingly. That was wrong. It was the requested IXUS 800 IS 100B.
I got confused by Canon's great names and numbers. My ixus850 / sd
800 has FW 100d... But that wasn't asked for here