PPC - Yaboot - How to configure the PPC Bootloader - Multibooting

[tiresia]

This is a short how to, in order to understand how to fix your boot problems.

1. ofpath is a utility to determine the OpenFirmware path of a device. If you want to know the OpenFirmware path of a device, e.g. /dev/sda3, just run

ofpath /dev/sda3

2. A minimal PPC-Linux Partition Table (without any MacOS) on /dev/sda looks like this

        #                    type name                  length   base      ( size )  system
/dev/sda1     Apple_partition_map Apple                     63 @ 1         ( 31.5k)  Partition map
/dev/sda2         Apple_Bootstrap bootstrap               1600 @ 64        (800.0k)  NewWorld bootblock
/dev/sda3         Apple_UNIX_SVR2 myLinux               85852160 @ 1664      ( 40.9G)  Linux native
/dev/sda4         Apple_UNIX_SVR2 swap                 8000820 @ 202238668 (  3.8G)  Linux swap

You can edit a partition table in Linux with mac-fdisk
Yaboot is on the second partition, the Bootstrap Partition. Do not mount it!


3. There are three ways to install yaboot on a Apple_Bootstrap Partition:
ybin
ybin is the bootloader installer for PowerPC based machines
ybin installs the bootloader according to the parameters in /etc/yaboot.conf
ybin uses ofpath to find the path to the bootstrap partition and to any defined macos/macosx partitions.
mkofboot
is a symlink to ybin, with the difference that initializes the bootstrap partition prior to running ybin to install the bootloader on it
yabootconfig
Yabootconfig creates a default configuration file and then runs mkofboot to complete the bootloader installation

4. The yaboot-configuration-file
A simple /etc/yaboot.conf in a dual-boot system with Linux and MacOSX looks like this

boot=/dev/sda2
device=/ht@0,f2000000/pci@7/k2-sata-root@c/k2-sata@0/disk@0:
partition=3
root=/dev/sda3
timeout=100
install=/usr/lib/yaboot/yaboot
magicboot=/usr/lib/yaboot/ofboot
enablecdboot
macosx=/dev/sdb3

image=/boot/vmlinux
        label=Linux
        read-only
        initrd=/boot/initrd.img

image=/boot/vmlinux.old
        label=old
        read-only
        initrd=/boot/initrd.img.old

boot= the bootstrap partition
device= openfirmware path to the root partition
partition= number of the root partition
root= the device name of the root partition

timeout= Sets a timeout in seconds for keyboard input. If no key is pressed for the specified time, the first image is automatically booted.
enablecdboot
macosx= device name of the MacOSX partition

There are more interesting options (for a complete list see 'man yaboot.conf') such as
macos= device name of the MacOS9 partition
password= to specify a password for starting the system
defaultos= to specify from wich os the computer starts
enableofboot
enablenetboot


After any changes of the yaboot.conf file, in order to make yaboot aware of the new 'situation', you need to run always

sudo ybin -v

5. MULTIBOOTING
For any other Linux-OS you install, the yaboot installer specifies in the yaboot.conf file following parameters:

image=/ht@0,f2000000/pci@7/k2-sata-root@c/k2-sata@0/disk@0:4,/boot/vmlinux
    label=sda4-Linux
    root=/ht@0,f2000000/pci@7/k2-sata-root@c/k2-sata@0/disk@0:4
    append="root=/dev/sda4 ro quiet splash"
    initrd=/ht@0,f2000000/pci@7/k2-sata-root@c/k2-sata@0/disk@0:4,/boot/initrd.img

image= the openfirmware path to the kernel-image (or to its symlink)
label= the name of the Linux kernel to display at the second yaboot prompt
root= the openfirmware path to the root partition
append= any options to pass to the kernel before starting
initrd= the openfirmware path to initrd

When you start the computer, at the yaboot prompt, you can choose which OS you want to boot from (Linux, MacOSX, MacOS) or if you want to boot from a CD (if in yaboot.conf there is the option enablecdboot). After you choose to start from Linux, if you hit TAB, you will find a list of the different Linux-Kernels for each installed Linux Distro. With the option 'label' in the list above, you can specify the name for each of them.

Usually you do not need to configure your yaboot.conf file. But it can happens, that the Linux Installer fails to detect other Linux Distros installed on the computer (for me, by installing Fedora 10, the installer did not detect my Debian and Ubuntu partitions).
Since I never had a problem with the Debian Installer, if I want to install different Linux Distros, I run Debian after the Installation of the others - it detectes the other MacOS or LinuxOS's always correctly.


6. In Ubuntu Hardy (8.04) ofpath fails to detect the correct openfirmware path in some PowerMac g5
The problems for some PowerMac G5 come from the ofpath utility, because it fails sometimes to find the right openfirmware path (sometimes, not always: on my PowerMac G5 it works well).
Even if you set in the /etc/yaboot.conf the right Open Firmware path, yaboot will not work correctly, because ybin and mkofboot need to run again ofpath (that is buggy)

SOLUTION
There is a fix for the ofpath, that you can download here:
https://bugs.launchpad.net/ubuntu/+s...ot/+bug/122607
(It was fixed in Ubuntu Intrepid 8.10 - thanks to PeterXw!)

If you download the ofpath.gz on your Desktop run

zcat Desktop/ofpath.gz > Desktop/ofpath

To overwrite the buggy utility with the fixed one just

sudo cp Desktop/ofpath /usr/sbin/ofpath

Now you can test if you get the right Open Firmware Path

ofpath /dev/sda2

You can now just run

sudo yabootconfig -b /dev/sda2 -r /dev/sda3

The -b option specifies where the bootloader is, the -r option is the 'root' device.
Change the bootloader and the root devices according to your Partition Map (actually you shouldn't need to specify the root device)
Say yes, when you are asked, if you want to run mkofboot


·······
USEFUL LINK
http://www.alaska.net/~erbenson/

·······
I hope I was quite clear (sorry, but english is not my first language). Feel free to suggest any corrections.

[pxwpxw]

I updated the launchpad entry with the ofpath.gz (previous attachment was full text script)

I think it will need chmod +x to make executable ofpath.

The Intrepid version yaboot package with the fixed ofpath is
$ dpkg -l yaboot
yaboot 1.3.13a-1ubuntu5 Yet Another Bootloader

Attached is yet another gzipped copy of that ofpath.

[mfox]

Very useful information, tiresia; thanks for posting this. I discovered on my own that not every distro does a proper job of configuring the yaboot menu, but Ubuntu and Debian do. Here's a question - what is /dev/sda1?

[tiresia]

In my example /dev/sda1 is the Apple Partition Map.
Here some informations:
http://en.wikipedia.org/wiki/Apple_Partition_Map
http://developer.apple.com/technotes/tn2006/tn2166.html

[concorde106]

Man, if only I found this when I was still dual-booting my PowerBook G4... If I reinstall Ubuntu I'll use it! Thanks! Although, isn't sda for Macintel, and hda powerpc? My AlBook G4's partitions are called hda...

[tiresia]

Although, isn't sda for Macintel, and hda powerpc? My AlBook G4's partitions are called hda...

No, sda (sdb,sdc, ...) refers to SCSI, Serial-ATA and USB Devices, while hda (hdb, hdc, ...) refers to IDE Devices. For a FloppyDisk you have /dev/fd.

In your PowerBook g4 you have IDE-Disks, therefore your device is /dev/hda

http://en.wikipedia.org/wiki/Device_...ng_conventions

[MemphisJones]

I have a dual boot iBook G3 with Hardy one hda3 and Intrepid on hda4. I would like for Intrepid to be the default partition, so do I just add to my yaboot.conf file "default=hda4-Linux"? Secondly, I installed Hardy after Intrepid on hda3 and its yaboot.conf file makes note of the hda4 partion, to add my default option to the file do I add it to the yaboot.conf located on hda3, or does it matter? Lastly, i prefer the Hardy splash screen to Intrepid bc in Intrepid the colors are all wonky but they are fine in Hardy (the correct orange/red/yellow logo with orange progress bar). Is it possible to somehow copy the Hardy splash screen to the Intrepid partion? What file should I look for and what all involves in changing that? Sorry for all the questions.

[tiresia]

I have a dual boot iBook G3 with Hardy one hda3 and Intrepid on hda4. I would like for Intrepid to be the default partition, so do I just add to my yaboot.conf file "default=hda4-Linux"?
Secondly, I installed Hardy after Intrepid on hda3 and its yaboot.conf file makes note of the hda4 partion, to add my default option to the file do I add it to the yaboot.conf located on hda3, or does it matter?

First of all: backup you yaboot.conf

sudo cp /etc/yaboot.conf /etc/yaboot.conf.bak

The file /etc/yaboot.conf is not a configuration file for yaboot but for ybin. According to the parameters in that file, ybin installs yaboot on /dev/hda2. Therefore doesn't really matter, if /etc/yaboot.conf is on /dev/hda3 or /dev/hda4

The option 'defaultos=' (please, notice it's defaultos not default) is usually used to specify an OS other that Linux (macos, macosx, bsd). If it is not specified yaboot will boot a Linux Kernel (after a time delay as in timeout).
At the second step, if you hit TAB, yaboot lists the names of the Linux Kernel on your computer, the first being the 'default' Kernel on the partition shown in 'partition='

Anyway, in your case, if you add 'defaultos=sda4-linux', it won't work, becaus 'sda4-Linux' is just a label, a name for the Linux Kernel, it is not the partition nor the root of that Kernel.

The easiest solution for you is just to boot in Intrepid (/dev/hda4) and run

sudo yabootconfig

It will set Intrepid as first Linux System to boot. If you want to edit yourself your yaboot.conf just as exercise, post it here and we can do it together.

Lastly, i prefer the Hardy splash screen to Intrepid bc in Intrepid the colors are all wonky but they are fine in Hardy (the correct orange/red/yellow logo with orange progress bar). Is it possible to somehow copy the Hardy splash screen to the Intrepid partion? What file should I look for and what all involves in changing that? Sorry for all the questions.

You can have a look here to get more information about 'usplash'
https://help.ubuntu.com/community/USplash
https://help.ubuntu.com/community/US...omizationHowto

[MemphisJones]

I actually got kind of ansy last night and tried on my own after reading "man yaboot.conf". Thank you for explaining the relationship bt ybin and yaboot, I didn't know that exactly. I edited the yaboot.conf file on my partion number 3 (hda3) just bc it comes before hda4. And like you suggested I made a copy of my file before I started editing. Anyways I added "default=hda4-Linux" and that worked I did not need to use "defaultos" bc I only have Linux on this box. I will add my conf file, but I have to boot into the other partion to get it. Thanks for the links on the usplash; I haven't figured that out yet but hopefully those links will head me in the right direction (i haven't read them yet).

[MemphisJones]

Here's my yaboot.conf file. The only thing I changed was the "default=hda4-Linux". So from what you are saying about ybin I could put this in my hda4 partition and and it would work. Does it matter that this file has the added bit about "# This entry automatically added..." at the bottom?

## yaboot.conf generated by the Ubuntu installer
##
## run: "man yaboot.conf" for details. Do not make changes until you have!!
## see also: /usr/share/doc/yaboot/examples for example configurations.
##
## For a dual-boot menu, add one or more of:
## bsd=/dev/hdaX, macos=/dev/hdaY, macosx=/dev/hdaZ

boot=/dev/hda2
device=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:
partition=3
root=/dev/hda3
timeout=100
install=/usr/lib/yaboot/yaboot
magicboot=/usr/lib/yaboot/ofboot
default=hda4-Linux
enablecdboot

image=/boot/vmlinux
	label=Linux
	read-only
	initrd=/boot/initrd.img
	append="quiet splash"

image=/boot/vmlinux.old
	label=old
	read-only
	initrd=/boot/initrd.img.old
	append="quiet splash"

# This entry automatically added by the Ubuntu installer for an existing
# Linux installation on /dev/hda4.
image=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4,/boot/vmlinux
    label=hda4-Linux
    root=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4
    append="root=/dev/hda4 ro quiet splash video=ofonly"
    initrd=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4,/boot/initrd.img

# This entry automatically added by the Ubuntu installer for an existing
# Linux installation on /dev/hda4.
image=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4,/boot/vmlinux.old
    label=hda4-old
    root=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4
    append="root=/dev/hda4 ro quiet splash video=ofonly"
    initrd=/pci@f2000000/mac-io@17/ata-4@1f000/disk@0:4,/boot/initrd.img.old