To reset the AVR - there's absolutely no need for a display.
The setup an ATV correctly, the case Ernie is referring to required the AVR to be bypassed and for the ATV to be connected directly to the display.

So in a nutshell, a 'headless' device like a source often needs configuration outside of an AVR / switch / matrix as they can default to settings that are incompatible with those types of products... which tells you everything you need to know about those particular sources.