On Mon, 12 Oct 1998, Jeffrey Ohlmann wrote:

> I have a Q650, running NetBSD 1.3.2 with a generic kernel.  The machine is 
> very nice when it's up and running, often for weeks at a time.  When 
> circumstances make it necessary to shutdown & reboot, the following 
> sequence of events occurs, with alarming regularity:
> 
> 1. shutdown -r from NetBSD; Mac reboots and I get chimes of death and a 
> sad mac.
> 2. Restart Mac.  Boots into MacOS fine.
> 3. Boot NetBSD.  Boot proceeds a short way and then the kernel panics.  
> Reboot from the debugger.  Mac OS boots fine.
> 4. Boot NetBSD again.  This time a nasty kernel panic with pages and 
> pages of errors flying by.  Restart the Mac with the power button.  MacOS 
> boots fine.
> 5. Boot NetBSD again, and this time no problems, we're back up and running.

Here's a shot in the dark: have you tried zapping the PRAM?