That seems to be a counterfeit version of the DM500 (neither Dream Multimedia nor DreamBox signs can be found on the box/unit), so I wouldn't count much on the build quality of the device. If it's based on the DM500, it should have 32MB of RAM onboard, not enough even for OS4, and I guess the memory can't be expanded, too.
Wiki page:
http://en.wikipedia.org/wiki/DreamboxVarthall
