[syslinux] syslinux mkisofs hard-disk-boot isohybrid

Pascal patatetom at gmail.com
Wed Dec 28 01:10:34 PST 2016

2016-12-22 10:19 GMT+01:00 Thomas Schmitt via Syslinux <syslinux at zytor.com>:

> Hi,
> Didier Spaier wrote:
> > The issue is the inability of booting of a *physical* (not virtual)
> optical
> > media, like for instance a DVD or a CD, using syslinux.efi.
> Actually firmware cannot find any UEFI specified booting starting points
> in an ISO 9660 filesystem that was created with mkisofs -b and
> -hard-disk-boot, but without a boot image which was marked as EFI System
> Partition.
> The boot success with UEFI and -cdrom must have other reasons. I suspect
> the BIOS emulation of the firmware.

I used "OVMF-pure-efi.fd" and not "OVMF-with-csm.fd" (from

> Do we really have confirmed examples where SYSLINUX EFI software works
> from qemu DVD-ROM ? Decisive test would be to make an ISO which offers
> no El Torito boot image for BIOS, but only an EFI System Partition image as
> El Torito boot image for Platform Id 0xef. In that partiton image there
> would have to be SYSLINUX stuff - not GRUB or a directly bootable kernel.
> Why i doubt:
> When it comes to reading data, there should be no perceivable difference
> between a real optical drive at a real computer and the virtual DVD-ROM
> of qemu. Both get operated in the end by SCSI commands.
> Of course there could be some driver shortage in SYSLINUX which does not
> show up with qemu DVD-ROM but prevents use of modern hardware. But i
> understand that EFI itself is a little operating system, which is supposed
> to operate hardware, and that SYSLINUX EFI software uses the API of EFI
> to perform its hardware operations.
> Have a nice day :)
> Thomas
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