Thank's for your answer.
I need to have the monitor on the back of the GoPro when I connect the HDMI cable to the GoPro.
With witch version of the firmware have you tested?
Yes, Page 33 in manual explains all. Shame I was not directed to the manual when first bought, Would have saved me a lot of questions.
I wonder if I can use the usb-c out to hdmi instead of the micro hdmi?