Ditto the pull card out at start up, put it in after. Does not have same problem when using Navionics card.
I should still have a version of 1.6 (or older) on my computer at home. PM me and I will see if I can figure out how to email it. I had it emailed to me from Lowrance when I had problems with “upgrading” to 1.7.
The GPS on mine has been fine but I do lose bottom at WOT much more than with previous Lowrance units I have had. Also have the problem with menus disappearing. When that happens I reload the software (very easy and quick). But then I have to re-do my screen set up preferences. This most often happens when I am switching between portable and boat mount.
On the plus side, it does a better job for hardwater walleye fishing than the Marcum LX5 I tried and returned last winter.