Hello guys. I have the same issue.
Onkyo 3030 w Triggers out for Zone 2 and 3. No main as I can see it (which is really stupid of them!).
In any case, I can turn on my amps by:
1. pressing zone 2 select
2. pressing ON
Then I press "receiver" and I control zone 1 again.
BUT I have a question. I use 7.1.4 config (4 atmos speakers). And have 3 amps (pre out for front and center). DOES ME TURNING ZONE 2 ON screw anything up? Like some speakers not working, or less watts to my main speakers etc etc? I don't like workarounds, but what can you do.
BR
Tony