Re: xorriso and EFI boot images

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Seth Goldberg wrote:
> BTW, See Fedora's genisoimage for a good example of how they do it.
> http://fedoraproject.org/wiki/User:Pjones/BootableCDsForBIOSAndUEFI

Thanks for the hint.
Ahum ...
  -eltorito-alt-boot -e images/efiboot.img -no-emul-boot

In man mkisofs of 2.01.01a64 and in
  http://svn.debian.org/wsvn/debburn/cdrkit/trunk/genisoimage/genisoimage.1
i see
  -eltorito-alt-boot
but not
  -e
So the latter is probably a Fedora extension to
mkisofs.

The description is very similar to what i
implemented as --efi-boot.
But -no-emul-boot is implied by --efi-boot and
we are not in sync with the size of sectors:
The web page talks of 2048 where i use 512.

As far as El Torito 1.0 is concerned, the case is
clear: Figure 5 - Section Entry talks of
"virtual/emulated sectors". Paragraph 1.5 defines
a Virtual Sector as [0x]200 bytes. A CD sector is
[0x]800.
But is EFI following this convention ?


Vladimir ? 512 or 2048 ?


Since -eltorito-alt-boot is part of original
mkisofs i will use the same option for my
emulation.
It will be implicit with --efi-boot.

I will have to ponder about implementing
option -e .
Anybody has a man page where it is described ?


> For maximum compatibility, the BIOS entry (platform id 0) should be first.

Well, it seems that option -eltorito-alt-boot
gives the user the freedom to do it different.
Since it is easy to do it right, i am in doubt
whether it is worth to force the user.


Have a nice day :)

Thomas