Attached is a Rockbox build for this player.
Remember you need to have a microSD card for this and copy the .rockbox folder
to the root and then flash the image file.
The build can work for many other generic rk27xx series players with buttons and
a 400x240 screen layout, but it will be a matter of trial and error at your own risk! be sure you can restore your original firmware first and good luck!
p.s anyone wishing to develop this further you can check out the source code at
http://www.rockbox.org/