Question about microSD data cards

I see that some of the latest Garmin receivers accept microSD data cards. I
know that Garmin offer the cards pre-loaded with maps.

Do any of the Garmin handheld receivers allow the user to use the unused
memory of the map cards or add data to a blank card?

Yes you can add to the unused memory, also add to blank memory cards.

You can find the preloaded maps here.

http://www.globalpositioningsystems.co.uk/c-software-sel.html?search=nuvi

I have a 60CSx with a 2G microSD card preloaded with Topo Great Britain.

I was not supplied with the Topo on DVD, which means that I cannot set up
routes, etc on my PC(it's much more convenient than setting up routes
directly on the 60CSX). The Topo maps cannot be transferred to Mapsource on
my PC.

However I do have Garmin Europe Metro maps on my PC in Mapsource.

I decided to load a few European Metro maps of France to the 60CSx unused
part of the microSD(there is quite a lot of unused space).

To my great suprise and consternation, the Topo maps were wiped from the
microSD card and replaced with the maps of France! I don't remember a
warning or I hit the Enter key or mouse button twice by mistake.

I had expected the Topo maps to have been somehow protected and locked and
undeletable from the microSD card. I was wrong. The whole .img file was
replaced(as usual) with the new .img file containing the maps of France.

Fortunately, I had some time ago backed up the Topo .img file onto my PC, so
I was able to recover by reloading the backup to the microSD card via my
card reader.

I had also backed up the Topo .img file to a spare 2G microSD card, but when
I placed it in the 60CSx it is not useable. The Topo is matched to the
microSD card's identity.

So be aware.

Keith G. Powell