>> However, the hp300 kernel is normally linked as a NMAGIC executable.

in sys/arch/hp300/stand/boot.c:
...
>	if (read(io, (char *)addr, x.a_text) != x.a_text)
>		goto shread;
>	addr += x.a_text;
!>	if (N_GETMAGIC(x) == ZMAGIC || N_GETMAGIC(x) == NMAGIC)
!>		while ((int)addr & CLOFSET)
!>			*addr++ = 0;

What is this?
--
I think that protected kernel text is better than
non-protected kernel text.  But, if you think
non-protected kernel text is no problem, then I see.