As long as both units are registered to your Garmin account using either ActiveCaptain or Garmin Express, you are able to download maps to your own SD card through Garmin Express. Plug your Lakeview G3 card into a card reader that's plugged into your computer, open Garmin Express, and register the card. You'll then be able to download maps to your own SD cards, but they'll only be unlocked for units registered to your account at the time you download them.