You can enter "-a" at the boot prompt which will cause the
kernel to ask you where the root disk is. Then, you can
build a kernel thusly:
cd /sys/arch/i386/conf
cp GENERIC MYBOX
vi MYBOX
change: config bsd swap generic
to: config bsd root on sd1 swap on sd1 dumps on sd1b
config MYBOX
cd ../compile/MYBOX
make depend bsd
mv /bsd /bsd.old
cp bsd /
reboot
- todd