Booting

This project is intended to boot on a variety of machines. They might all have a slightly different boot process, so describing that requires a somewhat more comprehensive document than a section in the installation instructions.

Supported environments

Generally, the live media support three types of environments primarily.

1. Bare metal OpenPOWER (PowerNV) – This includes machines such as Raptor Talos 2 (or Blackbird) and various IBM (and non-IBM) OpenPOWER hardware using the OPAL stack. These systems can boot ppc64le and ppc64 media and use Petitboot+kexec as their bootloader of choice.
2. Non-OpenPOWER IBM servers based of Slimline OpenFirmware (SLOF) – This includes various IBM Power Systems (pSeries) that do not use the OpenPOWER stack. Their firmware of choice is SLOF, which is a variant of OpenFirmware. GRUB, present on the live media, is used as the bootloader. This ia also the default kind of firmware you will get in virtualized qemu environments by default, so it’s important for KVM. They can run ppc64le for POWER8-and-newer based stuff as well as ppc64 for all of them.
3. NewWorld PowerPC Macs – This includes various G3, G4 and G5 based 32-bit and 64-bit Apple hardware. Only NewWorld hardware is supported for the live media and installer (i.e. G3 Blue and White and newer, as well as all G4 and G5; the old Beige Macintoshes can’t directly boot Linux). This hardware is based on Apple’s variant of OpenFirmware. Therefore, GRUB from the live media is the bootloader. They can run ppc64 images (for G5) and ppc images (for G3, G4).

There may be more environments that should be able to boot. For example, the IBM IntelliStation POWER 185 is an IBM workstation based on OpenFirmware and the PowerPC 970MP (IBM’s variant of the G5) and has all the prerequisites for being able to boot Void. Therefore, it most likely does, but it’s not tested, and may require workarounds (such as manually booting the GRUB image from the OpenFirmware console).

Bare metal OpenPOWER

Since the firmware of these systems is based on a small Linux system and it uses kexec as the boot mechanism, that makes booting the live media very simple.

All you need to do is put the contents of the live image onto any storage media the firmware can read (optical media, USB sticks, etc.) and the Petitboot bootloader takes care of the rest.

Remove the USB stick, then insert it into your OpenPOWER system, and wait for Petitboot to come up. The entries for live OS boot should show up. Proceed with installation or whatever else you need.

SLOF (virtual machines, pSeries, etc)

Unfortunately, I don’t have a physical SLOF system available, so this section could use expansion.

In a virtual machine, just specify the ISO image as a cdrom or a drive and make qemu use it as the boot device. GRUB will automatically come up. Then proceed with installation and so on.

NewWorld PowerPC Macs

If booting from optical media, this is straightforward; all you need to do is insert the media and boot from it in the usual manner (for example, using the boot device chooser).

Booting from USB is also possible on any NewWorld Mac, but may be slightly more tricky.

So if you want to boot from USB, insert your USB stick in your Mac, then power it on and hold the Command + Option + O + F combination. On standard non-Apple keyboards, this is Win + Alt + O + F. Keep holding the combination until your display comes up.

Release keys to continue!

This should be written on the screen, so release the combination. You will get a prompt:

 ok
0 >

G5 machines

The good news is, the G5s define the ud device alias, which matches the USB storage media you have inserted, at least as long as only one USB stick is inserted.

You can simply boot your Void like this:

boot ud:,\\:tbxi

For multiple USB media, it should be possible to use numbered ud:N. You can list all the defined aliases with the devalias command.

If this doesn’t work, you can try to boot the GRUB image directly.

boot ud:,\boot\grub.img

A GRUB menu should come up.

G4/G3 or if it doesn’t work

This is slightly trickier. Since the alias is not defined, we must create it. First, list the whole device tree:

0 > dev / ls

This will present you with a long listing, most likely also telling you to press Space for more, as the whole listing does not fit on the screen.

A simplified listing on my PowerBook G4 looks like this:

...
ffXXXXXX: ...
ffXXXXXX: ...
ffXXXXXX:  /pci@f2000000
ffXXXXXX:    /...
ffXXXXXX:      /...
ffXXXXXX:      /...
ffXXXXXX:    /usb@1a
ffXXXXXX:      /device@1
ffXXXXXX:        /keyboard@0
ffXXXXXX:        /mouse@1
ffXXXXXX:      /device@2
ffXXXXXX:        /keyboard@0
ffXXXXXX:        /mouse@1
ffXXXXXX:        /interface@2
ffXXXXXX:    /usb@1b
ffXXXXXX:      /disk@1
ffXXXXXX:    /...
ffXXXXXX:    /...
...

And so on. This basically represents the tree of all the devices attached in your system. We are looking for USB, and within that, we are looking for a USB disk.

In this case, you can see it under /usb@1b as /disk@1. Depending on the hardware as the USB port you use, this may look different.

Anyway, we’ve found the USB disk. Let’s alias it as ud.

0 > devalias ud /pci@f2000000/usb@1b/disk@1

This should print ok. Obviously adjust the values for your own device tree, you just need to join it all together.

Print the alias listing again:

0 > devalias
...
...
ud        /pci@f2000000/usb@1b/disk@1

Now that you can see it’s there, proceed with booting:

boot ud:,\\:tbxi

If that doesn’t work, try loading the GRUB image directly:

boot ud:,\boot\grub.img

A GRUB menu should come up.

Post-GRUB

Once you have selected your option in the bootloader, loading Linux will commence. You might see some messages like:

error: can't open device
Press any key to continue...

You don’t need to press anything and these errors are harmless. Just wait (it might take a minute or a few) and eventually Linux should load.

Proceed with installation and so on.

Yaboot

If GRUB for some reason won’t work and there are no available workarounds, we also ship yaboot as a fallback. You can boot it from the OpenFirmware console as well. Just replace this:

boot ud:,\\:tbxi

with:

boot ud:,\boot\yaboot conf=ud:,\etc\yaboot.conf

The conf argument may not always be necessary but generally is, as it will otherwise often try to use incorrect media to look for the config file.

Other OpenFirmware machines

These are not tested but should still work, as long as the CPU is good enough to run your variant. The instructions will likely overlap with those for SLOF or for Macs. Feel free to submit modifications for this chapter.

Serial console

By default, the system will boot assuming output on your monitor. If you don’t have a monitor, or for some other reason need to access the system via the serial port, you need to enable it.

Just proceed booting as usual, and once at the GRUB screen, edit the menu item you want to boot and append something like this:

console=tty0 console=hvc0

This applies for machines such as the Talos 2, Blackbird or qemu pSeries virtual machines. There is a special initramfs hook which makes sure to enable the appropriate agetty service for the console. The supported values are ttyS0, hvc0 and hvsi0. If you don’t need output on your monitor at all, you can skip specifying console=tty0. But keep in mind that for the hook to work, the console for the serial needs to be last! Otherwise the hook will not pick it up.

Other hardware

That’s completely untested, so if you manage to get something to boot, instructions to include here would be much appreciated.