US maps for Start 25, not compatible?

littlefi Registered Users Posts: 4
Apprentice Traveler
Hi I'm off to the US in April and really don't want to hire a sat nav when I have a perfectly good one here, so I just tried to upgrade to US maps and put in Sat nav a Start 25, and it says it's not compatible, is this correct? Am I not able to install them?

Thanks for help!