HDMI / ARC stopped working on two separate systems

[Cornan]

I recently realized that two of my Sony receivers (in different rooms) had both stopped outputting HDMI signals to the two connected televisions.

 

Both systems were working fine for 2+ years before "it" happened.

 

I've already been through a paroxysm of powering off and reconnecting cables but have not reset memory in any device (other than powering off).

 

The larger receiver has TWO HDMI outputs, and I eventually discovered that it is happy to output video on the non-ARC connection.  I can even switch between the two outputs using my remote and when I select the ARC output the signal stops.

 

The smaller receiver only has an ARC output and so I can't get a signal through it.

 

I suspect a software update.  The television connected to the larger receiver is from 2014, and while it shouldn't be getting system updates it does appear that at least one of the apps ( YouTube I think ) have been updated.

 

Both receivers have a Roku (could they have initiated something I've seen referred to as an HDCP lockup?), and the second television is an Android TV and has received updates recently.

 

I should mention that one of the Roku's gets  unhappy about HDCP every few days , even when connected directly to the television .

 

I am reaching out for any further insight on possible causes and steps to fix.  I'm trying to avoid resetting the larger receiver as it has assignable inputs and will take a while to reconfigure.

 

And of course I'd like to feel that what I do makes some kind of sense.