I have installed none of the upgrades and Zone 2 alone works fine either with the main on or off. I was able to turn on Zone 2 without the main being on.

I'm a bit confused though, do you have trigger 1 running to the 7125?

I wonder if it has something to do with using the two "open" channels on the 7125 as a Zone 2 amp. I run a separate amp for my Zone 2.