Be very, VERY careful with this. Rockbox is only "officially" supported on a limmited number of players, and a good rule of thumb here is that if it isn't officially supported or even mentioned in a passing way on teh website, it won't work. ALso, doing so might (depending on the player you have) void the waranty on your MP3 player, meaning you'll have to pay for a new one and lose all your music if you don't konw how to restore the original firmware.