It’s probably a Hidden FAT32 partition. You can use linux’s fdisk to change the partition type without wiping the data, but nevertheless I’d do a full backup of the card using dd and work on the image file instead. Maybe there is DRM? I distinctly remember being told that there wouldn’t be DRM and it would be totally open so you could simply copy the music over to your collection if you wanted to.
Openness sells. Closed off stuff makes me regret buying it, and usually involves a trip back to return the item…
