Boot Unix thru TU58 on Vax 750?

[cattani at columbia.ARPA]

From:  Bob Cattani <cattani at columbia.ARPA>

I need to boot Unix from a one-drive Vax 11/750 system (Eagle with
Emulex SC750) whose drive unit number is not zero.  (That's because the
disk is dual-ported to another system that has other units).  Hence,
the Boot ROM, which only boots from unit zero, doesn't do me any good.

If I understand correctly, the Boot ROM reads "hpboot", or whatever,
from the beginning of the disk; hpboot will read /boot from an hp disk
of any unit number (the program can be changed); /boot then loads unix.
So, if I could put hpboot on a TU58, I'd be in business, right?

If not, why?  If so, how can I do it?  I understand that TU58 on 750's
are hard to communicate with.  I've also heard of some MRSP PROM which
we don't have.

Thanks to all wizards.
-Bob Cattani, Columbia U CS Dept. (cattani at columbia.arpa)