This is my first post here so please excuse me if I am posting in the wrong place.

I've had no luck putting a new map on this Nuvi 660 with F/W 4.90.

With most Garmins I usually put the gmapsupp file into a folder called GARMIN, put it on a SD card, pop it into the slot and goto Map Info and tick the box to let the unit see the new map.

Sometimes the unit will require a software update in order for it to see the map on the card but this unit seems to be up to date regards firmware but it still won't see the unlocked map.

The map I am trying to put on is around 4Gb.

Is it possible the Nuvi 660 can't see a map of this size? Or has Garmin sent a firmware update to stop the Nuvi seeing the unlocked map?

Any help would be greatly appreciated.

Cheers

Derry