Handbook:PPC64/Blocks/Bootloader

With the kernel configured and compiled and the necessary system configuration files filled in correctly, it is time to install a program that will fire up the kernel when the system boots. Such a program is called a boot loader.

On Linux/PPC64 we have yaBoot as a bootloader.

Introduction
In order to find the boot devices, yaboot needs access to the device nodes created by udev on startup and the sysfs filesystem. These two filesystems are found at and  respectively. Early in the installation, these locations should have been bind-mounted into the chroot.

To set up yaboot, either use to automatically create a configuration file or manually configure the bootloader. When installing Gentoo on a Power Mac G5 (where does not always work), or when the system needs to boot from FireWire or USB, then manually configuring yaboot is mandatory.

Installation
Install the appropriate version of yaboot for the system architecture and type:

For 32-bit :

For 64-bit :

Default: Using yabootconfig
will auto-detect the partitions on the machine and will set up dual and triple boot combinations with Linux, Mac OS, and Mac OS X.

To use, the drive must have a bootstrap partition, and must be configured to reflect the Linux partitions (note that the Bootstrap partition should not be in the fstab file). These steps should have already been completed before, but check before proceeding.

Now run :

First, the program will confirm the location of the bootstrap partition. When using the suggested disk partitioning scheme, the bootstrap partition should be. Type if the output is correct. If not, double check the file. will then scan the system setup, create a configuration file, and attempt to run. The command is used to format the bootstrap partition, and install the yaboot configuration file into it.

It may be necessary to run command manually to install the bootloader:

After installation, verify the contents of. When making changes to (like setting the default/boot OS), make sure to rerun  (as root) to apply changes to the bootstrap partition.

Alternative: Manual yaboot configuration
An example file is given below, but it will need to be altered to fit personal preference.

Once is configured, run  to format the bootstrap partition and install the settings:

If is changed after the bootstrap partition has been created, then update the settings by running:

For more information on yaboot, take a look at the yaboot project.

Using yaboot on IBM hardware
On IBM hardware it is not possible to run or. Proceed with the following steps:


 * Emerge the yaboot-static package.
 * Run the following command, filling in  with the disk and partition for the PReP partition. {{Path|/dev/sda1}


 * Construct a file and place it into . Take a look at the configuration example above, look into the man page for  (, or look at the below  example.
 * Assuming the boot device in OpenFirmware is pointing to the hard drive the prep boot partition is on, then it'll just work. If not, at IPL time, go into the multiboot menu and set the boot device to the one with the prep boot partition.

That's it!

For POWER4, POWER5, and blade-based hardware (where the PReP disk partition and the disk partition that contains the kernel are on the same physical disk), it is possible to use a simplified. The following should be sufficient:

To verify that yaboot has been copied to the PReP partition:

A match signifies that yaboot was installed correctly.