“Send to Device” button greyed out / no confirmation — did it work?

Yes. In PurrOS 2.0 the button fades while sending and there is no confirmation sound or dialog — changes go live to the pedals immediately (unlike 1.0, which fully reset the pedals on every send). Settings are stored on the pedal hardware, not in PurrOS memory, so you can close the app and race.

If changes genuinely don’t propagate and PurrOS offers the same “minor USB fix” firmware update on every launch: switch to USB 2.0, then do a full reinstall (deleting the app’s local files; a deep uninstaller like Revo helps).