[sclug] isolinux weirdnesses

[David Given]

I'm currently constructing a live-CD-based Linux system for use as a media 
box. This is going quite well, apart from one minor problem. My CDs won't boot 
on my Shuttle box any more.

I'm using isolinux as the boot loader (are there any other Linux CD boot 
loaders?). The iso is being created with:

	mkisofs \
		-J -R \
		-o image.iso \
		-b isolinux/isolinux-debug.bin \
		-c isolinux/boot.cat \
		-no-emul-boot \
		-boot-load-size 4 \
		-boot-info-table \
		target

target is the directory containing my target filesystem. Inside it is an 
isolinux directory, containing:

-rw-r--r--  1 root root 1040413 Dec 12 00:05 bzImage
-rw-r--r--  1 root root   10500 Dec 12 00:05 isolinux-debug.bin
-rw-r--r--  1 root root      87 Dec 12 00:05 isolinux.cfg
-rw-r--r--  1 root root      19 Dec 12 00:05 mediabox.msg

isolinux.cfg is:

	default dis
	prompt 1
	label dis
		kernel bzimage
		append root=/dev/hdc init=/bin/init

So you see, this isn't exactly complicated.

What's happening is that the Shuttle doesn't seem to be recognising that 
there's a bootable disk in the drive, and is going on with the rest of the 
boot sequence (trying to boot off the network, despite the fact I explicitly 
told it not to --- I'm not impressed with the Shuttle's BIOS). I'm getting 
*no* messages from isolinux.

The really weird thing is that (a) it used to work, and some old CDs with an 
earlier version of dis (my media box software) still boot, and (b) the new CDs 
boot fine on my desktop machine.

I have tried the following things:

(a) using a fresh CD-RW, in case my old one had died and the Shuttle's DVD 
drive wasn't reading it correctly. Didn't work.

(b) tried booting any other random disk I could find on the Shuttle. All 
worked. (I use Geexbox regularly on it.)

(c) ditto, on the desktop. Works.

(d) swearing. Didn't work. Next step is to find a chicken.

Can anybody suggest anything before I try the extreme measures (firstly, using 
floppy emulation, which I hate with extreme prejudice, and secondly, replacing 
the Shuttle's DVD drive)? There's obviously some weird interaction going on 
between the Shuttle's hardware, the BIOS, isolinux, and something about the 
filesystem, possibly because it's just passed 40MB, although I can't see how 
that could matter. isolinux is pretty freaky at the best of times, and this is 
getting really, really annoying.

-- 
[insert interesting .sig here]