I was able to get a copy of the US and Canada disc image file which I have stored on my computer. I copied it to an SD card into a directory names Garmin and it's not showing up. Do I need to rename it? Right now it's named gmapsupp. The other directory on the card is named maps and has a bunch of topo maps that do show up. The file is 2GB could this be installed directly on the Nuvi 65LMT replace the original file and if so how does one go about doing it. Jim