Blue & White PowerMac G3: Open Firmware “Boot Manager”

Wait a sec, there is no such thing as an “Open Firmware Boot Manager” for the B&W PowerMac G3.
What Clickbait is this! — Correct. But wait! Read on first, because chances are, you are looking for the exact same thing like me, figuring out how to make OS multiboot somewhat working on the B&W PowerMac G3 …

In short, but you know that already, don’t you: The Open Firmware multi-boot routine is broken, if you hack in the “multi-boot” command, it will just hang forever. Also things like the OPTION key for enter a graphical boot menu, as seen on later Macs, didn’t exist on this machine.

I did a video about the B&W PowerMac G3, and how to effectively multi-boot different OS versions, like Mac OS 8, Mac OS 9, Rhapsody and Mac OS X 10.0.

This small tutorial is just a written resume of what I showed in the video, straight forward.

1. Boot into Open Firmware by pressing CMD+OPTION+O+F on power up, just shortly before or while you hear the Apple boot chime. Release the keys once the Open Firmware prompt shows up.
   
2. On the Open Firmware prompt, enter *nvedit* to open the NVRAM editor.
   It’s a line-based editor, with not much comfort, but you’ll find some good hints on how to use it at the NetBSD MacPPC documentation.
   
3. Now, enter line by line, each OS partition to boot as a devalias command, like this:
   
   devalias OSNAME /path/to/boot-device
   
   The path to the boot-device will vary depending on your system and partition layout.
   
   In my case, I had an Adaptec SCSI controller with a SCSI hard drive in SCSI ID 0 in my system, so the base path for the boot device is this:
   
   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:
   
   If you’re booting from the first IDE device, the base path might be something like:
   
/pci/@d/pci-ata@1/ata-4@0/disk@0
   
   The second IDE device would be something like:
   
   /pci/@d/pci-ata@1/ata-4@0/disk@1
   
   In any case, please adapt your device IDs according to your actual boot device, and the partition number.
   Don’t just blindly copy my device strings below, because they’re guaranteed to not be the same on your machine!
   
4. Once the list is complete, hit CTRL-C, then run the nvstore and nvquit commands
   
5. Configure Open Firmware to use the stored nvram-rc script:
   
   setenv use-nvramrc? true
   
6. Then reset the machine:
   
   reset-all
   
7. Enter the Open Firmware again the same way as noted in step (1)
   
8. If you did everything correctly, you should now see the devaliases stored permanently when running the devalias command:
   
   devalias rhapsody /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:6,\\:tbxi
devalias cheetah /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:11,\\:tbxi
devalias macos91 /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:10,\\:tbxi
devalias macos86 /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:9,\\:tbxi
   
9. Then boot the desired system, by calling up the boot command with the desired OS devalias, e.g.
   
   boot macos91

This will give you the closest of an interactive “boot menu” or “boot manager”. Not exactly comfortable, but still good enough to get the job done.

Below I included a full sequence, how to edit the nvram, generously borrowed from the NetBSD manual and adapted for this small tutorial.

Thanks for reading and hope it helps!

[POWER ON, press CMD+OPTION+O+F during boot chime]
0 > nvedit
devalias rhapsody  /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:6,\\:tbxi
devalias cheetah   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:11,\\:tbxi
devalias macos91   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:10,\\:tbxi
devalias macos86   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0:9,\\:tbxi
<C-c>
0 > nvstore
0 > setenv use-nvramrc? true
0 > reset-all
[REBOOT, press CMD+OPTION+O+F again during boot chime]
0 > devalias
[lots of output]
rhapsody  /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:6,\\:tbxi
cheetah   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:11,\\:tbxi
macos91   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0,0:10,\\:tbxi
macos86   /pci@80000000/pci-bridge@d/ADPT,2940U2B@2/@0:9,\\:tbxi
0 > boot [devalias], e.g.
0 > boot rhapsody