A week ago, LinuxDevices.com announced that Garmin opens source code of software used on their Nuvi 8xx and Nuvi 5xxx devices.
Now, it’s confirmed that Garmin uses Linux and GNOME software, more precisely, they use GNOME Mobile platform All packages are published on dedicated webiste http://developer.garmin.com/linux/
I found that garmin product is of high quality albeit the price is also a bit high but it’s worth paying.