I bought a Mk 1 Sport today only to find my house wasn't on the navigation unit. My SD Cars is a version 3. I've been doing some research and the Mazda BT50 uses the same maps and a similar if not the same unit. Where is has promised BT50 owners an update as of April this year, if they got that I have no idea. The unit by the way is a Bosch Navi 900 if that helps. This info and more I found at this link:
http://www.austech.info/gps/83090-fo...d-sat-nav.html
Hopefully there will be a solution!