I loaded the new firmware with no problems.

The issue with losing bottom lock you mentioned is normal on my unit. That is what I was complaining about when I first got the unit. It happens when the sensitivity is set for deeper water and you go shallow before the auto-sensitivity can reduce it. I think it saturates the processor. I get around the issue by setting the manual sensitivity to a low setting and then turn on auto-sensitivity. This normally allows auto-sensitivity to reduce the sensitivity fast enough and low enough to keep the display from freezing.