Error 9 when updating Sonos
Error 9 occurs when there is an issue with downgrading your Sonos system firmware.
This can happen when the Sonos S1 Controller app tries to perform an update while the Sonos system contains a mix of products running S1 and S2 software. To fix this, you can either remove the S1 products from your system or you can downgrade the S2 products to S1.
To downgrade the S2 products back to S1, follow the steps in our downgrade process article and then add them back to your system using the S1 app.
Error 9 can also occur after you remove yourself from a Sonos beta program and the Sonos players are transitioning back to general release firmware. If you see this error after leaving a beta program, contact Sonos Support for assistance.