Not sure it will help any, but are you (or anyone) sending any of these errors alongh to Navionics ???
Could be a serious problem one of these days for some unsuspecting boater. Probably not a major issues for people that have fish finder/GPCS Combos.
By thw way, did you get your new unit installed and did the guy contact you for the free old unit. The one I saw at Squam Rover Bait is still there, 110.00 for the complete unit.