[syslinux] isohybrid has 2 variants

[Didier Spaier]

Hi,

On 23/06/2014 12:07, Thomas Schmitt wrote:> Hi,
 >
 > i have written an introduction to isohybrid and put it on
 > the discussion page of the ISOLINUX wiki.
 >
 >    http://www.syslinux.org/wiki/index.php/Talk:ISOLINUX#Proposal_for_description_of_isohybrid
 >
 > Review and proposals are appreciated.

Caveat emptor: this is a review by an end user (not a developer), who don't
know the specs like that of MBR/GPT/UEFI and can hardly understand the meaning
and purposes of options of mkisofs or xorriso.

More specifically, I provide hybrid ISO images of polyglot installers for
Slackware on http://slint.fr/installers and http://slint.fr/testing

My goal is that  make these installers bootable on as many different hardware
and firmware as possible, including a wide variety of Macs.

So ideally I'd like to find in the documentation the commands to make very
versatile hybrid ISO images, and instructions to prepare the files' tree
before running these commands.

With this in mind, here are my remarks:

_Unde PC-BIOS you write:
The ISO 9660 production program xorriso can enhance its results by isohybrid, if an MBR template file from the local SYSLINUX installation is provided. The names of these files match the pattern isohdpfx*.bin and are to find in SYSLINUX directory ./mbr or installed as e.g. /usr/lib/syslinux/isohdpfx.bin.

But in ./mbr (Syslinnux-407) I find three files isohdpfx{,_c,_f}f.bin so
whare are their respective differences and/or use cases?

_When you write just before the UEFI title:
The result needs no further treatment by isohybrid tools.

I understand that means that after xorriso -as <options> CD_root there is no
need to run isohybrid <options> ouput.iso as output. ios is aleady hybrid.
Is that right?

_More generally, giving examples of isohybdrid commands in various use case
would be helpful.

_Under UEFI you propose a command "genisoimage <options> CD_root".
Would the options be identical if instead of genisoimage we use xorriso?
I ask as I'm not a Fedora user, thus don't have their variant of genisoimage.

_At the end of the page you give an example where the GPT equipment is added.
But in this thread:
http://web.archiveorange.com/archive/v/mwjwmhaWun4iHTR2s5Kg
you propose a command that would allow to boot on a Mac.

Could you provide such an example in the description of isohybrid?

Of course I'm a bit opportunist here as I'd like that our installers can boot
on a Mac without using rEFInd (I assume that I can use Matthew Garret's
hfs-bless as does Fedora in mactel-boot)...

So at least for me a command that would produce an image as versatile as
possible would e useful.

<OT>In Fedora-Live-Desktop-x86_64-20-1.iso  in macboot.img I see
among other files:
EFI
   BOOT
     BOOTX64.efi
     grub64.efi
System
   Library
     CoreServices
       boot.efi: same size as EFI/BOOT/BOOTX64.efi
       grubx64.efi: same as EFI/BOOT/grubx64.efi

Does someone know why two .efi files are needed and which commands are used
to build them?
</OT>

 > Not yet covered are:
 >
 > - The topic how to produce an UEFI boot image (FAT filesystem)
 >    which can be used with option -e of genisoimage or xorrisofs.

That's exactly what I need!

 > - The topic how to bring the isohybridized image onto an USB stick.
 >    (Especially on MS-Windows ...)

Maybe something like that can suffice:

On linux:
type "lsblk -f" to make sure you wont wipe out the wrong device, then
"dd if=<name of hybrid ISO image> of=<name of device> bs=1M"

On Windows:
use Rufus, cf. http://rufus.akeo.ie/