We used to use a home-grown 'mkzimage' script, found in ppc64-utils, for creating combined kernel+initrd zImages, for netbooting the installer. Now, we need to use the wrapper script exported in the kernel-bootwrapper subpackage. The attached patch (at git://git.infradead.org/~dwmw2/anaconda) seems to work. The final hunk is horrid though.
Created attachment 276511 [details] patch
Applied and cleaned up the final hunk too