hello today i installed the HDMI IN plugin see link: HDMI Input Plugin for DreamOS [.ipk / .deb] - DM 7080HD Other Files
the ipk where it is all about is the enigma2-plugin-extensions-hdmi-in_0.17_mips32el.ipk which is installable in the dreambox after that reboot the box and in the menu it has an entry HDMI INPUT.
next connect your computer with HDMI OUT to the HDMI INPUT from your dreambox input and after the computer boot up, go to the menu and select HDMI INPUT.

the picture will switch to the computer picture.