Was tweaking some pulsewidth on a tune on went to reload it. During the download, EFI gave me a message that the ECM had bad or missing calibration, but I could still load the tune. Everything appeared to load ok and the truck ran fine.

Well, I didn't like that error message, so I loaded the stock tune. Same error message, but again everything seems to load and run OK. Tried to load several other tunes and it's the same thing each time.

Anyone know what might have caused this or what to do to make it go away?