> > difference I can see from pdisk is that the non-working one 
> > doesn't have the "Apple_Driver_IOKit Macintosh" partition. My concern is that 
> > I was overzealous with deleting partitions.
>
> I don't think it always matters.
> I have two occasions both of which boot fine with simple
> pdisk setup.
>
> ===> Mac mini
> Partition map (with 512 byte blocks) on '/dev/wd0c'
>  #:                type name       length   base      ( size )
>  1: Apple_partition_map Apple          63  <at>  1
>  2:           Apple_HFS ofwboot      8192  <at>  64        (  4.0M)

What does hls -la show for your Apple_HFS partition?

It turns out my working disk (which I created with OS X) has an HFS+ 
partition (which I can't view with hfsutils) instead of HFS (OS X wouldn't 
let me create HFS). When I did an hls I wondered where ofwboot.xcf had 
gone!

Perhaps the sequence of steps should be in the FAQ? Here are some steps 
below with questions in [] - I'm a bit concerned by the weird partitions 
show with disklabel.

1) Check HFS partition exist and is at least 1MB in size
netmanager 1# pdisk -l /dev/wd0c

Partition map (with 512 byte blocks) on '/dev/wd0c'
  #:                type name        length   base     ( size )
  1: Apple_partition_map Apple           63 @ 1
  2:      Apple_Driver43*Macintosh       54 @ 64
  3:      Apple_Driver43*Macintosh       74 @ 118
  4:    Apple_Driver_ATA*Macintosh       54 @ 192
  5:    Apple_Driver_ATA*Macintosh       74 @ 246
  6:           APPLE_HFS boot          2048 @ 320      (  1.0M)
  7:     APPLE_UNIX_SVR2 root       1048576 @ 2368     (512.0M) S0 RUFS k0 /
  8:     APPLE_UNIX_SVR2 swap       1048576 @ 1050944  (512.0M) S1  SFS k0 (swap)
  9:     APPLE_UNIX_SVR2 user      57917807 @ 2099520  ( 27.6G) S2  UFS k0 /usr

2) Check partition name in disklabel
netmanager 2# disklabel wd0
disklabel: Invalid signature in mbr record 0
# /dev/rwd0c:
type: ESDI
disk: Maxtor 33073H3 B
label: fictitious
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 16
sectors/cylinder: 1008
cylinders: 59541
total sectors: 60017328
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0

7 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
  a:   1048576      2368     4.2BSD      0     0     0  # (Cyl.      2*- 1042*)
  b:   1048576   1050944       swap                     # (Cyl.   1042*- 2082*)
  c:  60017328         0     unused      0     0        # (Cyl.      0 - 59540)
  d:      2048       320        HFS                     # (Cyl.      0*- 2*)
  e:  59998356     18952  Apple UFS      0     0     0  # (Cyl.     18*- 59540*)
  f:        19  60017308    unknown                     # (Cyl.  59540*- 59540*)
  g:  57917807   2099520     4.2BSD      0     0     0  # (Cyl.   2082*- 59540*)
disklabel: boot block size 0
disklabel: super block size 0
disklabel: partitions a and e overlap
disklabel: partitions b and e overlap
disklabel: partitions e and g overlap
disklabel: partitions f and g overlap

[N.B. Where've partition e and f come from?]

3) format HFS partition
netmanager 3# hformat -l boot /dev/wd0d
Volume name is "boot"
Volume was created on Wed Aug  9 14:08:46 2006
Volume was last modified on Wed Aug  9 14:08:46 2006
Volume has 1030144 bytes free

4) copy ofwboot.xcf onto the HFS partition
netmanager 4# hcopy -r /usr/mdec/ofwboot.xcf boot:ofwboot.xcf

[Is copying as raw correct?]
[Do I need to set the creator/type?]

-- 
Stephen