[k2000] post-3.87J upgrade question

Hi,
I recently updated my K2000 to 3.87J. When I first did this, the next two restarts (after a hard reset) produced everything fine visually, but no audio.
Then I did a diagnostic run, and everything was fine. For a while. The next few days, I'd start it once a day and it was fine.
Then today, about 5 days after this seemed to be resolved, I started it up and once again -- no sound. All the data was there, all my RAM-backed stuff included, so it's not like I'm losing what's in memory. I restarted and it was fine.
Has anyone ever heard of anything like this?
- David