Running XPS13 9310 2-in-1 motherboard stand-alone

Hi, I bought the old motherboard from my laptop after having it replaced and I would like to run it headlessly, to create a server from it. When I connect it to a DELL DOCK and start it, it shuts down after a moment and never shows anything on an external monitor. However, when I take apart the XPS 13 9310 and connect its display and keyboard to the stand-alone motherboard, it does run.

How can I trick the motherboard to boot without any peripheries connected, except the DELL DOCK, where I have a USB keyboard/mouse and monitor connected?