Well, I had to fix several more problems, but I have my mono non-turbo
slab booting off an internal SCSI disk now.

One word of caution: both the NeXT ROM and our boot block will blow up
if the disk tries to initiate sync negotiate.  I had to jumper mine to
disable it.  If you boot off the network, the kernel will just reject
sync negotiation from the disk and work fine.