HDMI audio appears only when turn monitor off and on

[davids74]

Hi, I have an issue where on a computer I am building for customer where HDMI audio on Mac Mojave portion works only if you turn monitor off and on (you do have to have it on during boot to select OS, then once in OSX, turn off and on again). Everything is ok on Windows.
Motherboard is unknown (XCY mini computer), video is built in HD Graphics 6200, cpu is Kaby Lake i3-7200U. Everything works OOB except built in audio.

 

[toleda]

video is built in HD Graphics 6200, cpu is Kaby Lake i3-7200U

Not possible

 

[davids74]

Ups, sorry, it is HD 620. Well spotted!

 

[davids74]

Could we now proceed to the part where you tell me how to fix that?

There is a line in bootlog, "1:798 0:000 No AudioIoProtocols, status=Not Found"

Could that be that?

 

[toleda]

See AppleHDA HDMI Audio/Post #1/IV. Problem Reporting.
Post to thread linked with requested files attached.