Oh jeez, it's an embedded system that's 5 years old now. It probably doesn't fully (or correctly) implement the USB specification... because cost. Space constraints are likely similar, only so many bytes allocated for indexing/pawing through the connected media. >32 gb thumb drives wern't exactly commonplace circa 2013 when this was designed.
See if you can create a smallish FAT32 partition on something. You might have to fully wipe it first (like, full overwrite) then use a good formatting tool. I've had wonky results from windows formatting tools before, I use a linux system for low level disk work anymore.