Soundbar issue

Hello guys,
I have a tx5 pro connected to the TV via HDMI ARC cable to the HDMI 2 port. On the HDMI 1 port I have the soundbar. When the tx5 pro is switched on the TV is able to communicate with the soundbar and the sound is good. When the tx5 pro is switched off (standby) the TV can’t communicate with the soundbar (the display of the soundbar is switched on and the connection is blinking) so I can’t hear any sound from it but only from the integrated audio of the TV.
If I remove the power unit from the tx5 pro so there is no power or the HDMI cable the TV is able to use in the right way the soundbar.
Any idea? Is there some setting on Coreelec to avoid this issue?
Many thanks for any suggestion

I just discovered I have exactly the same problem with my Yamaha. It seems the coreelec device keeps the HDMI connection on even when the device is on standby.

Unless I remove my HDMI cable or the power outlet from the wall, ARC will not work between TV and HT.

Have you ever discovered a way to fix this issue besides having to remove the device entirely?

This is a problem with U-Boot. There is no fix for this.