I was thinking I’d run DietPi on the Sparky and load Roon Bridge. The Sparky kernel for DietPi has the Piano 2 drivers and firmware built in, which would get music into the Kali. After that I was just kind of hoping the Kali would send the right signal to the Spring, but maybe that’s a forlorn hope. I don’t need Roon to see the Spring, quite happy for it to recognise the Sparky as the endpoint.