You need an existing S1 system. If the S1 system does not already exist, then you need an S1 only product to create an S1 system, such as a Play:5 (gen1) speaker. You cannot create a new S1 system with a Playbase only, as it is both S1 and S2 compatible.

Here is a link showing a list of S1/S2 compatible devices…

https://support.sonos.com/en-us/article/sonos-s2-compatibility

You will need an S1 only required speaker.

Thx Ken

i already have an existing S1 system hence my frustration

Did you downgrade the Playbase first using the downgrade tool in the S2 App?

If not, see this link:

https://support.sonos.com/en-us/article/downgrade-a-sonos-product-from-s2-to-s1

Yes, done that.

then when trying to add it I just keep getting asked to update the S1 controller

Make sure you also remove the S2 App and if you have an existing S2 system, power off those devices. Open the S1 App to see your existing S1 system and then perhaps try the Playbase setup again via ‘Settings/System/Add Product’ in the S1 App.

Note there was a recent S1 update anyway - so just ensure the S1 system is up-to-date before you begin.

My S1 setup here is v11.9 build 571641110 if that may perhaps assist you further.

Done all that.

S1app still just asking for update ‍♂️

S1 is up to date matching yours

I think you are perhaps best to speak with Sonos Support Staff, as you appear to have done the things mentioned/expected - but note the Playbase will still need to receive the S1 firmware update when added to the S1 system, so perhaps check what you’re actually seeing on-screen and if still not happy, then Support will be on hand to assist you through the setup and adding the Playbase to the S1 HH.

Thx for your help Ken, I’m in a que for support, was trying all angles, have a great weekend 

It may help to power OFF all of the S2 units, close the S2 controller, and reinstall the S1 controller before attempting to add the downgraded player to the S1 system. If I was attempting this I’d uninstall the S2 controller too. Nothing critical is stored in the controllers, but they do try to keep track of which players were recently part of the system and this can cause some frustration when a controller claims that a product (you want to transfer to the other system) is “missing”.