@Scavvy
Many things like Voice *.vpm files cannot be run from the card however others like PIO *.gpi files and map ancillary files like JunctionView can be. Main System Software aka firmware can be updated by putting the later gupdate.gcd file in a Garmin folder on the card and rebooting. If you need to update Voice files then use the SD text command method to do that. BTW, did you check if it's an RWFS device? If so the path 2/: should work to access the card as i mentioned in Post #7. If you enable Mass Storage Mode and make RWFS visible using the Diagnostic Page (to access it either press Speed field then hold Speedometer, or press Volume Icon then hold upper RH corner, for ~5 seconds).