I realized after I posted this that I had started a similar thread in December of last year; my apologies for that.
Last night, I actually tried swapping out the HDMI cable connecting my 605's HDMI out to the display with a new one, and, lo and behold, the onscreen setup menu seems to be...
In response to our trusty Onkyo TX-SR605 (from circa 2007/2008, still going strong in our main HT system) showing evolving signs of its HDMI out port dying (at this point, sometimes I can't even get the menu to respond when I want to go back a page by hitting RETURN on the remote, aside from the...