[syslinux] Custom CentOS DVD, isolinux.bin, and isohybrid...

Bernd Blaauw
2012-06-22T18:10:26Z

Op 22-6-2012 13:20, Trey Blancher schreef:
> I was given a custom CentOS 5.4 DVD, containing some Digium software for
one of our customers.

I guess upgrading/replacing CentOS 5.4 is out of the question, even with
6.2 and 5.8 released.

With recent Isolinux versions, an Isohybrid file doesn't care in which
way it's booted (as CD, virtual CD or as raw harddisk image). The Linux
kernel won't care much either, but any initrd or init scripts included
with old distributions might not be able to handle booting from USB
Flash Device. In other words, the script loads drivers for whatever
interface an optical device would be connected to, then looks for the
medium (CD/DVD/Bluray) to find its needed data.

I suppose all of the following already worked for you:
1) ripping the disc
2) booting the disc
3) remastering the disc (contents) and verifying it's bootable
4) updating Isolinux and remastering + booting

You might want to have a look at how a mini distro like PartedMagic
handles booting and mounting ISO files from USB flash drive or even
system memory (Syslinux's MEMDISK component). Or more recent CentOS
incorporates these changes, perhaps allowing you to backport specific
scripts.