I have been happy with my Garmin (had ti sent from US with Thailand City Navigator 8.

Is there a way I can upgrade to Thailand Street Map 10?

I managed to download it (it says change the name to gmapsupp.img) and not sure what to do next.

The more convenient method would be placing GMAPSUPP.IMG within \Garmin folder of an SD card. Just simply create a New Folder at the root directory of the data card and rename it as GARMIN, and copy and paste GMAPSUPP.IMG into it. Then slot it in into device. Thereafter, you need to disable the older City Navigator map and enable Thailand Street Map at Map Info. A point to note that this map is originally locked and can only be used with the correct codes meant for the specific device Unit ID or data Card ID. If the one you're having now is the unlocked (hacked) version, then there would be no problem, but if it's a locked map, then you will need to have the correct codes for the map to work, or you'll get the "Can't unlock map..." message when booting up.

Thanks,

I have no idea if it is the hacked version. I found it in rapidshare search.

The more convenient method would be placing GMAPSUPP.IMG within \Garmin folder of an SD card. Just simply create a New Folder at the root directory of the data card and rename it as GARMIN, and copy and paste GMAPSUPP.IMG into it. Then slot it in into device. Thereafter, you need to disable the older City Navigator map and enable Thailand Street Map at Map Info. A point to note that this map is originally locked and can only be used with the correct codes meant for the specific device Unit ID or data Card ID. If the one you're having now is the unlocked (hacked) version, then there would be no problem, but if it's a locked map, then you will need to have the correct codes for the map to work, or you'll get the "Can't unlock map..." message when booting up.