I have an Roland MC808 Groove box. But I disliked the piano sounds.
So I downloaded some piano samples from the internet,

using the editor I created some new Piano sounds patches for the MC808.

If you have an MC808, then you can download the Compact Flash file for the mc808 here: http://www.dimmengestel.nl/CF_CARD_PIANO_MC808.zip 

Unzip the zip-file and copy the unpacked files to a formatted compact flash card.

Be sure you have made a copy of your MC808 data. I am not responsible for any data loss.

Your MC808 need to have enough expanded ram memory.