Given a bootable CD or DVD (either the medium itself, or the iso
file),
is there a way to extract the boot blocks from it
for use in creating a different bootable Cd or DVD? Would it even work?
The easiest way to make a custom boot cd is to modify the image of an
existing boot cd, copying whatever packages you want onto it, and then burn
the modified image to cd.
What exactly is your desired end result?