Thanks Rusty007. I upgraded my V50 without doing anything to the H50.
The V50 screen
now shows GPS
information where previously it only showed "No GPS
Information". The "Call" button on the Zeus2 AIS
page is now enabled, though I did not try it. The WX switching problem and other weird network problems were very intermittent before, so I can't really test if those have been corrected.
The H50 still works. The GPS information doesn't show on the screen
correctly, and the MENU is slightly messed up (the selected menu item does not show on the screen). I'm pretty pessimistic about finding someone to upgrade the H50. If that proves difficult, I think it is probably usable as-is.