Quick initrd note
This is mainly a note for myself, but someone else might find it handy. Working with modern initrds requires monkeying with cpio, which I can never remember the correct command line parameters for off the top of my head. So, here's a quick workflow (borrowed from Chip Shabazian) for manipulating an initrd image.
mkdir initrd cd initrd gzip -dc path/to/unzipped/initrd.img | cpio -id # Make the changes you need find . | cpio -c -o | gzip -9 > /path/to/new/initrd.img