Finally figured how to fix problem with Sonos Arc and Samsung TV compatibility issue.
- Use only Samsung remote - do not use other remotes otherwise you will have to start all over.
- Go to Samsung “GENERAL” and make sure Anynet+(HDMI-CEC) is activated (solid green dot)
- Factory reset Sonos Arc.
- Unplug all power and HDMI cables.
- Plug Sonos Arc into HDMI Arc/eArc. Plug in all remaining HDMI cables.
- Plug in Samsung TV power cable and turn on. Wait …. audio should automatically say "Receiver HDMI"
- Then one by one plug power and turn on HDMI connected boxes. Wait for Samsung TV to recognize each box so it's remote can control them.
- Hide all the other remotes so you don't have to do this all over again.