Thank you both Bob and Nigel for your feedback.
Did create NetBSD partition with Mkfs when I tried to install from MacOS
(Installer failure). In a second effort, when copying OS from 2nd HD to
internal one, I simply mounted latter's ufs partition which had previously
been formatted with Mkfs. Partition type *is* 'NetBSD Root & Usr'. It is
NetBSD's mount cmd (when booted from external disk) that considers both
/dev/sd1a and /dev/sd0d as 'ffs' (didn't tamper with FS opts in any way).
My Tuesday's mail and Booter's debug level 4 log are attached for reference.
Torsten

===FWD===
> Date: Tue, 17 Apr 01 04:54:43
> From: Torsten Kuehn
> To: netbsd-bugs@netbsd.org, Cc: sbrown@best.com
> Subject: mac68k-Installer fails to mount UFS partition

An annoying problem with mac68k-Installer v1.1.g (Oct 30, 1997) keeps
me from extracting base.tgz to successfully formatted root&usr filesystem.
Partition layout is as follows:
/dev/sda1 - 26.5k Apple Partition map
/dev/sda2 - 18.5k Mac Driver v8.1.4
/dev/sda3 - 20M Swap
/dev/sda4 - 2.0G ext2fs
/dev/sda5 - 2.0G BSD44 UFS
/dev/sda6 - 160M HFS
On startup, the Installer assigns sda4 to sd0a 'Root', sda3 to sd0b 'Swap',
sda5 to sd0d 'Usr' and sda6 to sd0e 'MacOS'. Consequently, it states
'failed mountfs(), error 22' and 'Error mounting root' (don't really expect
it to mount ext2 slice as /). Alas, the Linux kernel is compiled without
built-in UFS write support (still considered as experimental), so there
is no way to extract the tarballs to /dev/sda5. Any idea?
===FWD END===

===bootlog===
Logging to bootlog
Booting...
reading partition # 1 , partition name - 'Macintosh' 
reading partition # 2 , partition name - 'Swap' 
reading partition # 3 , partition name - 'A/UX Root' 
reading partition # 4 , partition name - 'NetBSD Root & Usr' 
reading partition # 5 , partition name - 'MacOS' 
reading partition # 6 Chose partition 3, name 'A/UX Root'
type 'Apple_UNIX_SVR2'
blocks in map 6, start block 41051, length 4049236
Magic from fs: 314574080
Magic from .h: 72020
Magic numbers do not match -- Improper UFS partition.
Could not open kernel "(0,?)netbsd".

*********** Boot Stopped. ***********
Restoring Monitor settings...
===bootlog END===