I have a mix of old and new Sonos components in my house running S1: 2xPlay:5 (gen2), a Play:5 (gen 1), Connect:Amp and a few more.

It happened twice that our kids or their friends see the Sonos prompt to upgrade to S2, and initiate the process without asking. They maybe think they're doing us a favor.

The first time we managed to downgrade all devices to S1. The second time not. One of the Play:5 gen 2 speakers refuses to downgrade.

I’m using the S2 app and follow all the instructions (reset/reinstall S2 app, reset speaker, etc.). The app finds the speaker and eventually starts the downgrade process. It shows a downgrading progress bar for about 3 minutes and then finally a message that it was unable to downgrade the speaker.
No details about the error.

I’ve tried this multiple times, with ethernet and wifi connection, I added the speaker to S2 and then completely removed and reset it. I read other threads on the same topic, but no solution found.

I probably spent three whole days in my life struggling with this S1/S2 incompatibility. I’m a software engineer and I’m pretty good at these things. Sonos managed to create a system where it’s super easy to upgrade, but very hard or impossible to downgrade. Their policy is extremely consumer unfriendly - it’s too bad because they have some really good products.

Any help appreciated.

Haavard