After long discussion, I finally got a written approval for getting the sourcecode for the RDC based LANDISK (in this case for the RDC 2891 chipset). But probably also usable for the RDC 2882 chipset as the way of firmware upgrade / firmware is the same.

As I am not into compiling and not want to brick any device I have on hand: greet my sponsors at http://www.aroundmyroom.com/landisk and than visit the rdc2891 folder to get the rdc2891.rar file

Use at your own risk. ;-)