For what I can see from a quick Google, it uses a distro that's called Angstrom. I have no idea what fs does Angstrom use. Are you following a wiki or manual that we can review to know what are you trying to do?
If so, please, point us in that direction.
Can you run the "mount" command without parameters and paste the output here? That will let us know what file systems is it using, and that way we can discard a problem with that.