How it works
foonas-em uses initramfs for the root filesystem these platforms. On boot the kernel unpacks the cpio/gzipped archive (contained within the kernel, although it could be a separate archive) into the RAM disk and runs /init, hence this process differs somewhat to the normal procedure because we use the kernel recipe to build the distribution.
Building foonas-em for the above platforms is possible (but not supported) in subversion revision 954 or newer. Note that the resulting files must be under 3670016 bytes to fit into flash, ie the sum of the kernel and dtb file sizes. It is up to you to check this.
Install foonas Sources
Follow the standard Installation Guide to the end, however do not build anything yet!
Firstly modify the DISTRO variable in your local.conf to foonas-em. If you built any packages before this (or have built for foonas already) trash the tmp directory. For example:
DISTRO = "foonas-em"
Now the kernel build file needs to know where your rootfs will end up so that when it builds it can compress it and archive it inside for use in the initramfs. Modify the defconfig in packages/linux/linux-linkstationppc/foonas-em/ and change the following line to a path that is relevant to your configuration:
The build process takes less than an hour on my machine, including building the toolchain (Yorkfield Quad).
$ cd /stuff/build/ $ bitbake linux-linkstationppc
You should now have .dtb files and a kernel with rootfs inside in tmp/deploy/uclibc/images/lsppchg (or lsppchg). You will only need the dtb file relevant to your platform for the installation.