We just pushed mkinitrd 4.2.15-13. This has a neat little patch I cooked up for the world: ISO Label support. Until now, nash's mount-by-label functionality didn't support iso9660 volume labels. In short this means you can now use the kernel cmdline arg 'root=LABEL=MY_CD_ROM' (for user defined variations of MY_CD_ROM) to boot straight to a cd without knowing the device node ahead of time. This is mainly useful for a bootable CD looking itself up, but I'm sure there are other cute little uses I haven't thought of.

One caveat: Spaces in your ISO label might be a little painful to deal with, so I wouldn't recommend it. If you label your CD for example: "my cd rom", the mount by label functionality in nash can find it, but the kernel command line is space delimited.