Upgraded OBP on Ultra 1 - now can't boot

Question

Started out wqith an Ultra 1 at OBP 3.5. Upgraded it to Solaris 9. During the install I was offered (but declined) the option to upgrade the firmware to 3.11.
System booted just fine - very happy.
Then in an attack of conscience, I decided to revisit the OBP issue. Downloaded patch 104881-08 from sunsolve, followed the instructions and upgraded OBP to 3.33 (current). Install went fine. Ultra-1/Solaris 9 was listed as a supported platform in the documentation.
Now, however, every time I start the machine, I see this:
Sun Ultra 1 SBus (UltraSPARC???? 167MHz), No Keyboard
OpenBoot 3.33, 128 MB memory installed, Serial #9415477.
Ethernet address 8:0:20:8f:ab:35, Host ID: 808fab35.
(Notice the ??? after UltraSPARC).
When I attempt to boot I see this:
ok boot
Boot device: disk File and args:
krtld: load_exec: fail to expand cpu/$CPU
krtld: error during initial load/link phase
panic - boot: exitto64 returned from client program
Program terminated
ok
The two seem to suggest to me that OBP 3.33 cannnot properly identify the CPU.
Now I have a non-bootable machine with no apparently easy way to revert to an earlier OBP. I have the Solaris 9 12/03 media kit but have not figured out how/if I can somehow get to the embedded 3.11 PROM I was offered earlier.
Has anybody seen this?
Is it a known issue with OBP 3.33? (I notice it purportedly fixed Bugid 1205113: "dev /SUNW,<a href="mailto:UltraSPARC@0" target="_blank">UltraSPARC@0</a>,0" fails. which looks suspiciously like my problem.)
Thanks in advance,

Answer 1

Remember, OBP is OS-independent so the fact you can't boot an OS doesn't mean you can't fix your OBP.
To do this, you have a couple of options I can think of:
Option 1. (Easy) If you have a CD-ROM installed on your box, you can unzip and burn the patch onto a CD. Then, from the OBP ok prompt, type:
boot cdrom /104881-07/flash-update-Ultra1-latest
Option 2. (Harder) If your shop has an installation or boot server on the network (e.g. a JumpStart installation), you can unzip the patch into that environment, making sure that it's located beneath the directory the Ultra1 would normally boot from. If you've never worked with any of Sun's over-the-net boot/installation tools before, either get some help or get ready for a lengthy (but doable) chunk of work.
Before attempting this, you will need to make sure of the following:
a. /etc/ethers has an entry for the MAC address of the machine you're trying to rescue
e.g. xx:xx:xx:xx:xx:xx some-host-name
b. some-host-name can be resolved in DNS
c. /etc/bootparams has an entry for some-machine-name
e.g. some-machine-name root=<your install server name>:/install-server/Solaris_9/Tools/Boot install=<your install server name>:/install-server boottype=:in rootopts=:rsize=32768
Note: the above assumes you're not using DHCP to supply the above information. If your shop uses DHCP, then you need to go and consult with the guy who set it up because I've no experience with that part of it.
Once your install server is set up, you can add the OBP patch to the installation.
In the example below, I'm using PATCH_TAR to indicate the tarfile you downloaded that contains the OBP patch and assuming your working with Solaris 9.
cd <install server main directory>
cd Solaris_9/Tools/Boot/platform/sun4u
mkdir flash
cd flash
tar -xvf PATCH_TAR
Now, you have a flash update image you can boot from the network like so:
boot net flash/104881-07/flash-update-Ultra1-latest
Option 2. is trickier but I know it works because that's what I ended up doing.