On Thursday, May 23, 2019 at 1:15:26 PM UTC-7, vtcyclist wrote:
Ron. Thanks for the suggestion. At the top of Craggy’s LXNAV page is the warning not to download LXNAV files with an Apple product. That solves the firmware problem.

Glad that worked for you. I've downloaded LXNAV files to my Apple MacBookPro many times and they always worked for me. Anyway, whatever works for you is what is important.