Etrex 20 hangs during download of topo map to SD card
I wanted to use the Northcentral topo map (Idaho, etc) but it was too big to load onto my etrex 20. So I bought a 64 GB SD card, thinking I could have several maps. I am using the Garmin app on a Macbook Pro running 10.10.5. The download proceeded through the first file and on the second file the progress meter when from -40% to -10% to zero and then stopped. I have tried two separate network connections. I've been looking for documentation on loading maps onto SD cards but haven't found any. The Garmin manuals are rather terse. Does anyone know how to properly load maps onto the extrex 20 SD card? Does anyone know of the practical limit on the number of maps it can hold other than memory size?