Just as a follow-up on my previous post:

I also confirmed that the clock still loses about 2 minutes/day.
The stock kernel also doesn't recognize the boot device, so I have to
tell it at boot time interactively.  My boot configuration is a HFS
partition with ofwboot.xcf on the root drive.

My custom kernel config usually gets around that with the line
config netbsd root on wd0a type ?

My workaround for the DMA issue is the line
wd* at atabus? drive ? flags 0x0f00

Joe.