I have the Asrock J4205-ITX, through the HDMI 2.0 port I cannot get 3D MVC and HD Audio Passthrough to my receiver and 4K TV as I reported earlier in the thread.
I plugged an old ATI DVI to HDMI adaptor into the MB and my HDMI to HDMI lead from the DVI adaptor to Marantz NR1606 receiver, at first I got no audio but this returned after installing the Realtek Audio driver from the Driver Disk, I now get:
4K 30hz
HD audio passthrough (DVI to HDMI Receiver)
3D MVC it auto switches to 1080p 3D 24Hz on my LG TV)
So effectively what you would expect from HDMI 1.4b, so if like me if you are not bothered with 4K 60hz and 10 bit at the minute, then this is the way to go until the DP-HDMI chip is patched.
NVidia and ATI graphics have been able to pass audio through DVI connection for quite a while, I have the Realtek audio driver installed from the Asrock Disk, and the audio is still through 'WASAPI - Intel Display Audio' in Kodi.
I now have a excellent 21TB NAS, and Kodi on the same machine using 18 Watts and 38 watts with all disks spinning (which is rare with Stablebit Drivepool/SnapRAID),
J4205-ITX NAS/Kodi Build, very happy.
DVI to HDMI adaptor is similar to this
https://www.amazon.co.uk/dp/B01LRSCPMO, the one I used came with an ATI graphics card.
@
flyingernst, Are your TV and Beamer 1080P 1.4b devices, maybe this allows the HDMI on the MB to bypass the DP-HDMI 2.0 chip, which is could be why you are getting 3D and HD Audio passthrough on your HDMI in Windows 10, just a thought.