Interesting Horizon Problem

[John Crane]

I have a NorthStar Horizon running Lifeboat CP/M. Everything works and the
wood is nice on the eyes too. However, it won't run the larger CP/M
programs (like Supercalc). The CP/M I'm running is a 48K version and I
suspect that's the problem. I've tried the usual MOVCPM business from 56K
to 50K, but no go. When I try the resultant OS, it locks up. A little
digging showed the boot ROM located way down at E800h. My guess is that's
what's blocking my use of a larger CP/M. Since 8080 code is
non-relocatable, I'd have to find some way to move that ROM somewhere up to
the Fxxxx region to get a bigger TPA. Anybody seen a CP/M utility to move
ROM code like that? Besides altering the code, I'm sure I'd have to tinker
with the controller card & CPU card to adjust the ROMs address and the CPUs
startup address to match. I've got a couple of ROM programmers lying
around, so that part is covered. Or, maybe I'm barking up the wrong tree on
this? Maybe there's some other inherent weirdness in the Horizion that I'm
overlooking.

-John