Never tried it on my stock MetroPCS froyo. So, I couldn't tell. I could boot with just the headphones plugged in, but I am having sticky issues with booting the CM7 rom. It seems to hang from time to time on the issue Android boot screen. When I do get it booted, it works amazingly well.
Except for the headphone and calls issue....
I've never been able to get it to work with CM7. It's weird. I think it's a software issue sending the signal to cut the headphones in call. Music and everything else works well on the headphones. I have no problems running napster or Google stock media player app.
The build I'm using is PlayfulGod's 06242011 build.