> sounds like the kernel things your root is _not_ sd0a.

After rebuilding again from scratch - and discovering same problem -
I took a look at the EEPROM stuff - and discovered that the boot file
(as a result of the previous owner's usage) was shown as 'linux'.

Changing it to 'netbsd' fixed the problem - but I do wonder how it
even managed to boot!

Not to worry - I'll write it off as a victory to the dreaded
Penguin ..

G.