Hi,
A word on what to expect from adding an echo statement: the echo may prevent the system from switching into a Picasso screen mode, but you should see a message indicating what's happening. On my system, the early echo causes a shell window to open to display the output. The system boots normally until it attempts to switch to a Picasso screen mode. At that point, a requester pops up indicating Intuition can't change the screen mode because a window is open (the shell window). When I dismiss the requester, the system finishes booting to Workbench using a native Amiga screen mode.
What happens when the system fails to boot? Does it hang indefinitely, do you get a software failure message, etc?
Did you have a monitor connected to the Picasso output when you saw a blank screen on the mono output? It looks like the relays only switch the color signals. The sync signals are switched by the nearby logic chip. If the system is booting far enough to open a Picasso screen, I think you'll get a stable blank screen on the monitor even if the relays have failed.
Robert