Help...I can't boot!

[Mark E. Hickey x4149 x4417]

In response to v9n4 "Help...I can't boot"

Part of the message said:

I then fscked all the xd6 partitions until fsck was happy, did an
"installboot /boot bootxd /dev/rxd6a" and thought that all would be great.
I then fasthalted the machine and tried to boot from the prom.  I tried
">b xd(1,6,0)" that died on a label read error (error #3).  I then tried
">b xd(1,2,0)" (since xd6 is the #2 disk on ctrlr 1) and that crapped out
with a BUS ERROR ! What am I doing wrong.  What is the best way to get a
twin root disk ???????  The filesystems on the xd6 "look" just fine; my
PROM just seems to hate to boot from anything but xd0. HELP ! 

This is just something to try....

In experimenting with installing boot blocks, I think I found out (it was
about a year ago, when 4.0 first came out) that you actually have to run
install boot using files from the disk you want to install the boot block
on.

It appears from your sunspots message that your "boot program" arguement
to installboot was the boot program (/boot) on your xd0a disk (which is
wrong), not the boot program on your xd6a partition (which is what you
should try using if you haven't already.  One way to do this is to mount
the partition you wish to install on and then specify the path to the boot
program on that disk; eg: 

  mount /dev/xy6a /mnt
  installboot -vlt /mnt/boot bootxd /dev/rxd6a

and then try to
  >b xd(1,2,0)

Installboot maps the block numbers of the "/boot" program mentioned on the
command line into the boot program boot{disk_type} and then writes the
result into the boot block on the specified device.  So using the boot
program from your xd0a partiton to install a boot block on your xd6a
partition will leave you with a boot program in your xd6a boot block that
contains an invalid list of blocks for the boot program that is invalid
for that partition.