[Bug-xorriso] Re: able to specify EFI boot-load-size?

[Thomas Schmitt]

Hi,

> When building an ISO with a secondary EFI boot loader is there any way to
> specify a boot-load-size that's smaller than the entire loader?  

> I tried adding another "boot-load-size" entry after the EFI param with
> no luck

-efi-boot is a specialty for grub-mkrescue. It allows no modifying
options but rather performs automatically -eltorito-alt-boot.
Option -e is less specialized.

So try
  -eltorito-alt-boot -e boot/x86_64/efi
instead of
  -efi-boot boot/x86_64/efi
and then make further settings as with option -b.
E.g.
  -no-emul-boot -boot-load-size ... 
 

To verify success you could read bytes 17*2048 + 71 to +74 as little
endian 4-byte word.
This gives you the 2048 byte block number of the boot catalog.
If you have one PC-BIOS image and one EFI boot image, then the
"Sector Count" of the second boot image is stored as little endian
2-byte word at offset 3*32 +6 to +7 of that block.
This number gives the load size in 512 byte blocks as it was set
with -boot-load-size.

There is a description of El-Torito booting in libisfs doc/boot_sectors.txt
resp. in GNU xorriso doc/boot_sectors.txt. Regrettably the statement
about "Sector Count" was misleading. Now corrected in
  
http://bazaar.launchpad.net/%7Elibburnia-team/libisofs/scdbackup/annotate/head%3A/doc/boot_sectors.txt


Have a nice day :)

Thomas