I'm having the exact same issue, tried burning SD cards with both Balena Etcher and Win32 Disk Imager. Interestingly I can hear Siri over CarPlay, so I know the speakers/amp are working. No other audio works and HD radio tuner broken.
Did you ever get yours sorted @EliC?
And thank you HondaR, Jamesl75, timcampbell092 for this thread and instructions helping people unbrick!