C236 WSI - onboard HDMI works but no VGA

I just got an ASRock Rack C236 WSI motherboard for a new NAS build. It seems to work fine apart from one thing: There's no picture on the onboard VGA (D-SUB) output. The onboard HDMI works normally though.

I tested this with 2 different monitors, 2 different VGA cables, 2 different CPUs (E3-1245v6 and G3900 - both with integrated graphics) and different RAM modules. I had this with the original v1.00 BIOS as well as the latest v2.10. The monitors simply go into power save as if no signal is present. I do NOT have a graphics card inserted in the PCI-Express slot.

Unfortunately I do not have any monitors supporting DisplayPort so I can't test that output.

Normally I wouldn't care much about VGA and just use HDMI instead but I intend to use this board in a rack with KVM switch that only supports VGA. I'm not really looking forward replacing the KVM switch (and monitor).

I double-checked the user manual and went over all BIOS settings but I couldn't find anything that suggests enabling/disabling the VGA output.

Am I missing something obvious or is my new board faulty? Thanks!