Autopilot looses calibration?

[wmcunninghamii]

OK, I finally had an opportunity to review and address SW versions. I found almost all of my gear was out of date, i70P, ACU (both 100 and 200) , the CCU, an i70 instrument and an i70s which I just purchased.

Whew, that all took about two hours to get updated. The good news is my preliminary checkout was good with the ACU 200. I still need to re-do the post software update re-calibration but so far so good.

The concern I have is why would a stable system with no equipment modification suddenly become unstable with the fix being software updates? This seems odd to me. Does this imply the software somehow becomes corrupted, has Raymarine seen corrupted software issues in their systems? It would be helpful to know this for future reference.