Can I load maps directly to an SD card during a map update?
The latest versions of Garmin Express and Garmin Map Updater offer the ability to install a map update directly to an SD card.

The SD card installation option will only appear when updating a compatible device that does not have sufficient internal memory for the largest allowable map region. When using the SD card installation option, critical files are loaded to the SD card so it must remain in the device after the update to ensure full functionality.