Strange FAT filesystem

My Garmin GPS device has a slot for an SD card. I'm using a 32 GB SD card which holds 22 GB data currently.

If I attach my device to a USB port it shows two devices, the internal memory and the SD card. I have no problems with the internal memory which holds only 2 GB of data.

I can mount both as a FAT32 system, but listing (ls) the large SD card based file system shows only rubbish (many question marks and dots).
Fdisk is telling me, it's a FAT32 partition.

BUT, when I start Windows7 under Virtualbox on the very same hardware, I can list the device just fine and CHKDSK doesn't find any errors. And Windows claims it's a FAT32 system.

I've even tried to execute mount.exfat-fuse but it cannot find an exfat file system.

Has anybody an idea what's going on?

Many thanks for a hint,
Helmut.

I do not know what you are trying to do, but Garmin plays really well with a program called GSAK. It is free download and works on Windows XP onword.

GSAK is primarily aimed at geocaching, but does a lot of things well with most brands of GPSr.

GSAK (Geocaching Swiss Army Knife)

I do not know what you are trying to do, but Garmin plays really well with a program called GSAK. It is free download and works on Windows XP onword.

Thank for the pointer to GSAK.
I'm trying to get access to the contents of the SD card with Linux tools only.
I'd like to mount the file-system but this doesn't work unless I know the type of the file-system.

Helmut.