I never tried copying music to it before. No I have not tried different Rockbox builds. How would I try this like how to install a different build? I don't have another computer to try this on and have no one that I could try this on their computer.
The instructions for updating Rockbox are in the first post. And in the menu of Emcore it's Tools -> fallback image. That build is a little slow, but a proper USB connection seems to work most of the time on it.
+1 this has become the norm. Don't forget to reboot after your done (menu+select).