Chromebox HDMI handshake failure

Hi,

I have the following equipment:
-Asus Chromebox CN62 (Celeron)
-Pioneer VSX-923 receiver
-Samsung UE65KS8000 TV

Chromebox is connected to receiver and receiver to TV via ARC port.

Libreelec 7.0.2 is installed in dual boot mode through EZ script.

Issue:
When powering on the Chromebox, the HDMI handshake seems to fail and the boot process stops, leaving me with a black screen. The only way I’ve found to boot into Kodi is to unplug the HDMI cable, power on the Chromebox and then insert the HDMI cable.

What I’ve tried, without success:
-Different HDMI cables
-Plugging the Chromebox directly to the TV (bypassing the AVR)
-Upgrading SeaBIOS to the latest version

I’ve read there have been quite a few issues with the Intel/Pioneer combo, but the Chromebox has the same behaviour when it’s directly connected to the TV, so I’ve discarded that issue.

Is there anything else I can try?

Thank you in advance for your help/tips.