Creating a bootable CD with CD Loader

[Chris]

Hi, I'm looking to create my own custom boot CD that will be used to
bootstrap fully encrypted system using GEOM ELI. All the CD needs to do is
load a kernel to initialize the encrypted root partition on the HDD, and
read a key file to decrypt it.

Ive looked at some tutorials for creating your own boot CD's but often they
seem overly complicated or old. It seems to me the easiest way to do this is
either: To use one of the FreeBSD floppy images and get it to boot from CD
correctly. Or to use the CD Loader that the the distributed FreeBSD CD's
use.

I ripped the CD Loader image out of one of the FreeBSD 6.1 CD's, and it
seems to work as wanted. It loads the kernel from the system I'm running at
the moment, I just put my current /boot directory on the CD (although it
doesn't fully boot, i guess it just needs some config changes).

But I'm a little wary of using something that i don't really understand.
Rather than just ripping the CD Loader out of an already made ISO i would be
interested in knowing how it is created. So i could create a bootable CD
without needing to borrow parts from a distributed one, and get a better
idea of how it works.

Any help appreciated.