How to activate HDMI output with FreeBSD running on a CM3+?

Hi all,

I have FreeBSD 14.2 running on a couple of CM3+ in a TuringPi 1.
That board features an HDMI connector wired to the first module.

Here's the block diagram:

https://docs.turingpi.com/docs/turing-pi1-intro-specs

I cannot get output to the connected monitor. Only thing I tried
- because all documentation a search engine finds is very Linux specific:

hdmi_group=1

or

hdmi_group=2

in /boot/efi/config.txt

Anything else i need to do in FreeBSD to get HDMI console working?
Monitor is saying "no signal".

Thanks in advance,
Patrick