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 have already been bind-mounted into the chroot.

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

Default: Using yabootconfig
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 yabootconfig, 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, install yaboot.

For 32-bit:

For 64-bit:

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. yabootconfig will then scan the system setup, create and run mkofboot. mkofboot is used to format the bootstrap partition, and install the yaboot configuration file into it.

Verify the contents of. When making changes to (like setting the default/boot OS), make sure to rerun   to apply changes to the bootstrap partition.

Alternative: Manual yaboot configuration
First, install yaboot on the system:

For 32-bit:

For 64-bit:

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 yabootconfig or ybin. Proceed with the following steps:


 * Install yaboot-static
 * Run  (fill in XX with the disk and partition for the PReP partition; this was in our example )
 * Next construct a file and place it into . (Take a look at the config above, look into the man page of  or look at the below  example.)
 * Assuming the boot device in OF 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 yaboot.conf. The following should be sufficient:

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

A match signifies that yaboot was installed correctly.