Maps on SD CArd

Yes, you can have your custom POIs loaded to the SD card. When running POI Loader, just change the default installation to go from the nuvi to the SD card. You can also manually move the file from the nuvi to the SD card using your computer with the nuvi/SD connected as long as you remember to put the POI file(s) in the proper folder in the SD card and remember to delete the nuvi's internal file. You may/probably need to fully power down the nuvi and reboot it for the device to find and use custom POIs in the new location.

On the other hand, custom POIs, even with a custom icons and audio alerts take up little space and with the map already on the SD card, the nuvi should have oodles of free space so I see no reason to install custom POIs to the SD card.

Thanks for clarifying this.

If they truly updated maps by using a blank formatted SD card, then assuming they used a sufficiently large SD card and it has free space, then you should be able to do as CraigW said. If however, they gave you a Garmin branded preinstalled map on SD, you may not be able to add additional files to the SD.

The nuvi 660 is one of those older devices that has a 2 GB file size limit, so it would be interesting to know if they installed the full NA map by splitting it into 2 files (one file on SD and one in internal memory), or if they installed a partial map like US and Canada or lower 49 states.