Updating multiple gps with one garmin disk
) You should become familiar with in particular the Ja Va Wa Device Manager for your gps and Ja Va Wa GMTK for the maps on your computer as these will sort out many issues you come across from time to time.
I attached my garmin nuvi 200 to my computer and drag and dropped the file into a folder on my garmin's sd card but still not getting maps.
I've just downloaded the Central America map from there, copied it to a "Garmin" folder on the micro-sd card on my Nuvi 265w, searched for "Belize" (via Where To / Cities / Spell) and got a map of Belize City.
To be more specific, the etrex saves the gpx tracks it creates when you go for a hike to the internal drive.
Any tracks you create on a computer prior to your hike to guide you, can be saved to the the gpx folder of either internal or micro drive and work fine either way. Bummer, but as you say, they are smallish files so can stay in main memory. One would hope that they should be able to be stored and read from the SD card.