I did manage to let the device boot up again by disconnecting the HDMI cable when I power on the vero, then a few seconds later I reconnect HDMI to the vero and the screen lights up with the osmc boot image.
Really strange behaviour. When I leave HDMI connected when power cycling then the boot process obviously hangs, because vero never comes up via SSH or ping.
Btw, I just ordered a new PSU from amazon with the specs you mentioned here (5V, 2A center positive, 5.5mm OD; 2.1mm ID).