[Fedora-livecd-list] syslinux vs GRUB (Was: Using both EFI and MBR at once on Live USB images)

[Jeremy Katz]

On Mon, 2008-10-27 at 23:03 -0400, Stewart Adam wrote:
> I've been testing out creating using a hybrid GPT+MBR stick so that EFI and 
> BIOS-based systems can boot off of the one stick and share a persistent 
> home. The good news is that it works and the changes are fairly simple - 
> essentially, I just removed the conditional statements that prevented the 
> non-mactel stuff from being executed when --mactell was passed. I also had 
> to rearrange a few blocks so that the GPT partitions happens first, since 
> the MBR should only be installed after GPT has initialized (and therefore it 
> will install to GPT's protective MBR).

Cool! 

> The bad news is syslinux doesn't support GPT at the moment because we can't 
> set a MBR partition as "bootable" in a GPT partition table. GRUB doesn't 
> seem to care about this and will boot fine once installed to /dev/sdb, 
> although the only bug I hit then was that booting from "USB-HDD" and 
> "USB-ZIP" in the BIOS didn't work... I had to select "HDD" and then choose 
> "USB-0". Is this why the scripts currently use syslinux instead of making 
> the jump to GRUB?

The biggest reason is that we use isolinux for CDs  (because grub's cd
booting code is incompatible with a fair number of machines) and using
the same bootloader for both live image over CD and USB is a good thing.

That said, syslinux definitely has better compatibility for booting off
of various USB things since hpa has spent a lot of time dealing with
BIOS bugs ;)   It might be worth sending a mail to the syslinux list and
see if hpa has any thoughts... he tends to be up for making syslinux as
usable as possible for everywhere.

> Even if we only use GRUB as a last resort (when --mactel is passed), I still 
> think this is a worthfile feature most recent motherboards support booting 
> from USB as a HDD instead of USB-ZIP.

Yeah, if we have to, I guess we could fall back to this.  But probably
at this point, it's too late for Fedora 10

Jeremy