I just got back from a week long trip in the Wind River Range of Wyoming and had some serious difficulties with my 66st (pretty sure the software is the same as 66i and only the power source differs). Here are the 2 main issues:
1) While hiking and recording the current track, the unit would suddenly switch from recording/displaying the normal track (using the default interval) to a point-to-point straight line track, drawn from the last location where it apparently made the unwelcome switch, to the current location. Not very useful for backtracking or anything else! Anyone know why this would happen? It happened on multiple days. The "fix" was to power the unit off and on, but obviously all of the missing breadcrumbs were still gone.
2) Fairly often, I was unable to scroll away from the current location to other parts of the map. That is something I do frequently to see, for example, how far we were from the next lake or whatever. However, at times, the displayed arrow (or cursor) could not be scrolled with any of the 4 direction buttons.
Any help is appreciated!
