I've been trying to run a 1.3G map on a 4G SD card with my Numi 205. When I hook up Garmin, the PC recognizes the internal memory and the SD card as separate drives. I've named the image file on the SD gmapsup2. Upon reboot the unit does not see the SD map. Thinking it may be a bad image, I renamed my working gmapsupp on the internal drive and moved it to the SD. After reboot, the secondary map is now gone. It reappears once I move it back internally. Current internal image files are gmapprom, gmapprom1, gmapsupp, gmapbmap and gmaptz. Am I missing something?