[syslinux] isohybrid: slint64-14.1.iso: unable to find mac efi image

[Didier Spaier]

HI,

In http://slint.fr/misc/MacBoot/ you'll find all context information. All
files referenced here are stored there.

Long story short: once dd-ed on an USB stick the ISO image can boot on
a BIOS or EFI machine, but I want it to be able to boot on most x86_64
Macs with an EFI firmware.

Unfortunately I get the error message:
isohybrid: slint64-14.1.iso: unable to find mac efi image

The script whose end is "mac_hybrid_image_mac_able.sh" is run on
a Slackware64-14.1 that ships syslinux 4.06 to prepare the mac-HFS+
image file (in addition to the two others already included) and build 
the ISO.

Here a few questions and remarks:
_I am aware of the recent patches of isohybrid.c .Is there a chance that
  using syslinux from git as of today enhance chances of success? Or could
  I just cherry pick part of the file tree (which one, then?) and back-port
  it to syslinux 4.06?
_I realize that it's probably a PEBCAK issue. Can anyone check the
  isohybrid command at end of mac_hybrid_image_mac_able.sh? in
  "man mkisofs" they are many HFS options, but I am not acquaited with all
  that stuff. Could someone help my find out which ones I should use? Or
  where else should I ask that if that's too much a newbie question here?
_Could my problem be related to a badly blessed file/directory? I just
  run hfs-bless (from Matthew Garett in Fedora's mactelboot package) on
  /system/Library/CoreServices/BOOTX64.EFI in the HFS+ file systemt hat
  will become macboot.img, but am not sure that's the right thing to do.
_On the same topic, I saw that now @ Fedora they don't use hfs-bless
  any more, see mkefiboot (shipped in lorax/src/sbin). Does somrone know
  why? The URL 
http://developer.apple.com/library/mac/#technotes/tn/tn1150.html
  to the he Technical Note TN1150: HFS Plus Volume Format referenced in
  mkefiboot is broken.
_Is there a chance that I'd succeed in using xorriso instead of mkisofs?
  I must admit that I never used it and the length of the man page is
  scaring me. I'd be very grateful to any Thomas who could happen to
  read  this and help me write the command ;)

Thanks in advance for any clue,

Didier

PS I guess that mkefiboot is used to build the installer in Fedora 20 
Live ISO.