Bumping an old thread because I have the same problem.
I have a VERY old operating system V1.05. Registered online, got the V5.04 download. Bought the sacred ScanDisk CF cards in the specified capacity. Power down, insert card..................and ...............nope, comes up just as the OP noted.
Not the card reader, it reads my various chart cards.
Not the card, I put in another C-80 (my spare) and it worked as advertised.
I'm betting that you need some incremental upgrade to get the damn thing to work. Raymarine says no, but I'm not buying
Anyway, we will see. I'll call Raymarine next week.
In the mean time any ideas?