Not sure I have ‘the’ answer for you, but if you’re downgrading to S1, the S2 app shouldn’t ‘see’ the S1 device, only an S1 controller. 

And, also, I’m not sure you could even ‘upgrade’ a ZP 90 to an S2 controller. It should only ever be seen by an S1 controller, if it is a ‘true’ ZP90. How certain are you of the item nomenclature?

Well you're correct, it’s not a ZP90… it’s a ZP80.  

I did an update today via the Sonos S1 app on my Mac.  And now it won’t connect via my iPhone… so went back to the Mac and it won’t see it either.  

As soon as open the S1 app, it tells me I have to use the S2 controller.  So I think somehow, it did try to update the device to S2?  But yeah, not compatible.  And Sonos support are the folks who told me I had to downgrade it but couldn’t get it to work.

Not sure a ZP of any type can be ‘upgraded’ to S2. They’re just too old, and don’t have enough RAM or CPU to run S2.

Do you have S2 devices? If so, I’d certainly unplug all of them while troubleshooting this issue. No need to tempt fate by having a second system out there trying to be identified by a controller. 

Next, and I know you’ve done this before, I’d try another factory reset of the ZP 80. Use the S1 mobile controller to set it up. Once it’s set up, you can connect to it using a desktop controller on your Mac, but I wouldn’t touch that Mac controller until such time as it is set up. The Mac controllers have had setup features pulled out of them years ago, you really should be focused on your mobile controller. 

Thanks.  And yeah, good. idea unplugging my S2 devices. 

I’m not worried about too many features. All I use the old system for is streaming music from my computer or from SiriusXM. 

I’m still trying to understand why support had me trying to downgrade to S1, and why the S1 app is telling me the device is S2.  But I’ll give your ideas a shot.. see if it works.  thanks!

We see a number of "things are confused" posts from folks doing setups with both S1 and S2 systems active, the turn one off usually works. Once setup things seem to work well together.

If you run both S1 and S2 systems on the same network the official apps can easily get confused.

I recommend an app that is designed to handle both systems simultaneously :-)