Well,

you've probably installed already, but here's a suggestion
anyway:

> The machine has 6.5 MB of memory, and can currently
> run BSD4.2 from hp style drives.
>
> It also has 2 ra81 drives (that I want to install 1.4.1
> onto.)

Ok, it's conceivable that the memory is a little tight.

> I have managed to manually (from the 1.4.1 miniroot
> single user prompt) disklabel both of the ra drives,
> copy the miniroot.fs from the tape to ra0a, install
> the boot block using disklabel -B, and even cold
> boot the miniroot from ra0a ....

Can you then turn on some swapping with swapctl?  Ideally it
ought to be part of the miniroot system.  That might get sysinst
to go a little further.

- H=E5vard