Is normal, any version have diferent JCV files, the .sum is a checksum file. Make always a backup of original files, then proceed with update, you can delete the Sum files.
You must have downloaded the mapsource version of the map. You must have the Garmin MapSource software and use it to make an img version of the map.
Hi kamoteka... This was crucial information, thank you. I am still in the dark though as to where I put the mapsource version of the map in order for mapsource to find it. Can you help? Thanks.