Recently the Siri Remote got an over the air update from Apple TV 4K. The version is indicated on Apple TV > Settings > Remote > .. Version 0x0070.

Since then the volume control (louder, quieter, mute) was not working anymore. I guess thats happened due to changes in the HDMI connection protocol or something.

To fix this

  • disconnect TV & Apple TV from power
  • disconnect the HDMI (required)
  • wait for few minutes ☕️
  • connect HDMI
  • power on

The fixes at Apple Support did not help.