Asrock J4205-ITX (Apollo Lake) DP to HDMI 2.0 Updating Firmware to 1.61 or 1.66 for Audio Pass-through Issue
To fix the HD Audio Pass-through issue with the MCP2800 DP to HDMI 2.0 chip, the firmware needs to be updated to 1.61/1.66 (the later seems to work better for me). 1.61 was provided by ASRock, 1.66 was direct from Intel, this link no longer works, and the latest version 1.72 does