[OPi Zero Plus 2] No HDMI when no monitor is connected

rumbero71

I try to get my OPi Zero Plus 2 working with a HDMI to VGA adaptor connected to a KVM.
Setup:
OPi---(HDMI)--->Adaptor---(VGA)--->KVM--->Monitor.
When booting the OPi with the KVM set to the port where the adaptor is connected, everything is fine. However, when the KVM is set to another position, OPi boots correctly, but when I am switching to the adaptor's position there is no video, just a blank purple-ish screen.
The same thing happens when booting entirely without display.
Is there any way to force the HDMI interface to switch on regardless of any display connected ? Or would it be possible to somehow reset the whole HDMI subsystem *after* booting in order to get an output ?