SUMMARY: Bootblock unable to read label

From: Robert M. Kuhn (
Date: Sun Jul 18 1993 - 15:16:11 CDT

I misposted a summary, which allows me to post a more complete one.
Well, I got many replies, a lot of which pointed me to earlier
summaries and, to my shame, a FAQ. My excuse is that the
answer to question 11 includes information which is not
really an answer to the question, and turns out to be incomplete in 2

1) the solution in the FAQ does not always work, and
   did not in my case, or that of
   "Everett Schell" <>
   There are 2 deficiencies in the FAQ.
   a) The FAQ solution applies only to Open Boot Proms prior to 2.6.
   b) I believe (but have been unable to check for sure) that it
      does not work if booting from drives other than sd0 (SCSI target 3).
      I checked this with Sun, in the person of Rick Tilson, and we
      believe the line "2: cd /sd" needs to be replaced with an
      appropriate one for the particular drive.

   I had tried the FAQ solution, not knowing about the Boot Prom
   restriction, before the flood of messages about it -- since I have
   Rom version 2.6, it failed.

2) I had been on the right track when I left the first cylinder
   out of partition 'a'. I thought I had pointed out that the
   exclusion was something I had tried as a solution, so that the
   many helpful replies pointing out that one usually starts at
   cylinder 0 were way off track.

   I do not understand WHY it works, but starting partition 'a'
   (the root file system) at cylinder 2 solved the problem. Many
   thanks to

   "Everett Schell" <> (Birger A. Wathne)

In summary, you can either exclude cylinders 0 and 1 from the first
partition on the disk (though not from 'c'!), starting partition 'a'
at cylinder 2 or follow the included advice from Rick Tilson. I have
not confirmed Rick's solution.

Here (somewhat abbreviated) is Rick Tilson's message:-

From: Rick.Tilson@Corp.Sun.COM (Rick Tilson)
To: kuhn@math

Here's a workaround:

 This applies to all systems with 2.6 or later Open Boot PROMs.

        ok nvedit
          0: probe-all install-console banner
          1: cd /esp
          2: ' 0 ' 1 ' timed-spin >body 7 /token * + token@ (patch
          3: device-end
        ok nvstore
        ok setenv use-nvramrc? true
        use-nvramrc? = true

1) Don't change the spacing in line 2 above. It's important!
2) If there is more than one "esp" node in the system (i.e., if you have more
   than one SCSI Host Adapter), then you must substitute the full OBP pathname
   of the esp node that has the Wren VII on it for "/esp" in the example.

Or, if your OBP is < 2.6:

        ok nvedit
                0: true to fcode-debug?
                1: probe-all install-console banner
                2: cd /sd
                3: patch 0 1 sstart
                4: device-end
                5: ^C
        ok nvstore
        ok setenv use-nvramrc? true
        use-nvramrc?= true

        Then power cycle. Subsequent attempts to boot from the Wren
        drive should be successful.

I replied:-

this is a new and different version of the nvram patch, 1-800-USA-4SUN
doesn't have it, they have the 2nd one. Does the second one
assume sd0? I assume that, just like the first, it assumes the
default for drive rather than bus.

To Which Rick responded:-

Yep. A better approach would probably be to just cd down the device tree
to the appropriate device, then do the patch.

----- Begin FAQ Answer 11 (extract) -----

        Note: Older Wren 7's may not boot on IPX's, ELC's and later machines,
        due to a bug in the Wren 7's firmware. Here is a patch to the NVRAM
        which must be made from the monitor. Only make this patch if you
        have prom revision 2.0 or greater:

        (from monitor level)
> n
        ok nvedit
          0: true to fcode-debug?
          1: probe-all install-console banner
          2: cd /sd
          3: patch 0 1 sstart
          4: device-end
          5: [ press <control> c to exit nvedit at this point ]
        ok nvstore
        ok setenv use-nvramrc? true
        ok reset

        WARNING : It is important that you type this correctly. Check this
                  several times! Remember all the question marks, dashes
                  and spaces and yes, sstart should be with two "s"'s.
                  Note: Syntax errors in your NVRAMRC can make your
                  machine unbootable. In Prom version 2.x, hitting L1-N
                  after the selftest at bootup will reset the NVRAM.

        (Thanks to nedre@gest20.SINet.SLB.COM for the Wren 7 fix.)

----- End FAQ Answer 11 (extract) -----

----- Begin Original Message -----

>From Thu Jul 15 04:42:07 1993
Precedence: bulk
Date: Wed, 14 Jul 93 16:13:16 EDT
From: kuhn@math (Robert M. Kuhn)
Reply-To: kuhn@math (Robert M. Kuhn)
Followup-To: junk
Subject: Bootblock unable to read label
Content-Length: 1023
X-Lines: 33

After obtaining a loaner disk I'm stumped on getting it booting.
Here's the setup:-

SparcStation 2, no internal disk, SCSI bus with 2 enclosures,
SunCD and Seagate Wren VII as sd3. SunOS 4.1.2 virgin install from CD.

I have booted from CD and installed the OS twice. In between,
the disk has been reformatted, repartitioned to start partition 'a'
at cylinder 1, the label rewritten, but when I try
to boot from the disk I still get

Bootblock: libprom.a: Romvec Version 2
Can't read disk label.
Can't open disk label package
Bootblock startup failed
Illegal Instruction

I can boot from CD, load the miniroot into /dev/sd3g, boot the
miniroot, mount the root and usr partitions. Everything looks
just fine. fsck shows no problems.

I'm stumped. The kicker is, this is a server for a network which
has now been down for 2 days -- help!

        Robert M. Kuhn
        Director of Computing in Mathematics
        Department of Mathematics
        Harvard University
        1 Oxford Street
        Cambridge, MA 02138

----- End Original Message -----

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