Updating garmin 200 nuvi maps
See Garmin nuvi 200W accessories to find the right one.
I have an e Trex 30 and have multiple differently named maps, all in the garmin folder on a 𝜇SD, but normally only have 1 or 2 enabled at once.
Where did you download the map from, and what exactly was the download link?
OSM doesn't make ISO images available, so either you downloaded the file from somewhere else (and would have to ask them why the file is broken), or maybe your system thinks that the file is an ISO image when in fact it isn't.
Please Note: your device may require the latest software update.
For further tips and help with installing and loading Garmin SD/micro SD Cards click here.