> > to /kernels and relocate the root partition to "d" or so. but then you have to
> > use the "netbsd on <blah>" in your kernel config. i did something similar with
> > root-FS on RAIDframe a while ago, but i don't know the exact steps i took then.
>
> The question is... how to specify the default kernel to boot in the
> bootloader, directory, name, etc.
>

bootloader can boot only from partitions root directory.

you may change default partition and filename in bootloaders source and
recompile.
/usr/src/sys/arch/i386/stand/biosboot/main.c

in case of i386