[See /usr/src/linux/Documentation/initrd.txt for more info on initrd.]

When "bootme" points to "../bootlinux", the bootlinux forth script instructs OF
to load yaboot via tftp from 192.168.2.1 (our "master" server) and yaboot in turn
uses the same IP to load its config file "yaboot.conf" via tftp.

Yaboot.conf then specifies the linux kernel image, again retrieved via tftp to "master",
and also the linux root device.  This can be either the preinstalled linux partition,
or a ramdisk filesystem derived from initrd.gz also transferred via tftp.