I have this same issue, using the most recent version of Rockbox & 2.1.5 L2. For some reason Rockbox seems to prevent my internal memory's files from showing up in the normal song list. I'd be interested in a solution. I'm not sure what you mean by updated the database, though, since I only installed very recently. I still don't have a clue what I'm doing with Rockbox so I tend to leave it alone.