Damn.

Mark, what did your 419/420 error messages mean? The brief flash of the "segfault error" and then the longer "sigkill error" whilst the unit was rebooting. Just after the reboot, it would flash the "segfault" again before being replaced with "sigkill".

I have now selected several playlists at random, including one that gave me a hda error yesterday, so far with no problems / errors. I will go out in the car later, as I'm off-shift, and do a more thorough test.