Re: Trying to create UEFI & Bios bootable .iso using xorriso

[Thomas Schmitt]

Hi,

larry wrote:
> I'm using xorriso to create an iso that boots on both Bios and EFI. The iso
> boots fine on a bios machine but isn't even recognized on an EFI machine.

You seem to have provided the necessary options for your xorriso -as mkisofs
run.

The combination of
   -isohybrid-gpt-basdat
and
   -e --interval:appended_partition_2:all::
is unusual. I advise to omit
  -isohybrid-gpt-basdat
because the resulting GPT is invalid anyways because of the two emerging MBR
partitions.

For clarity i advise to move
  -append_partition 2 0xef efi.img
before
  -e --interval:appended_partition_2:all::
because the former causes the partition to be added while the latter then
refers as target of the El Torito Catalog entry for EFI.


> foxclone025-02.iso1 *        0 1351679 1351680  660M  0 Empty
> foxclone025-02.iso2        276    5203    4928  2.4M ef EFI (FAT-12/16/32)

Partition 2 is lure for EFI if the ISO is presented on USB stick.

> Section Header Entry:
>    Header Indicator: 0x91 (Final Section Header Entry)
>    PlatformId: 0xef (EFI)
> ...
> Boot Catalog Section Entry:
>    Entry is bootable
>    Boot Media emulation type: no emulation

This is the entry in the El Torito Catalog. It serves as lure for EFI if
the ISO is presented on CD, DVD, or BD medium.

---------------------------------------------------------------------------

Now we are getting a bit off topic for this list. But i watch your efforts
in the stackexchange empire since a few days. Their captcha test does not let
my browser pass. So i only answered to the one direct xorriso issue using
a Debian 10 Live system.

The next thing to do would be to mount the file efi.img and to look whether
the boot program (made by grub-mkimage) is at the correct position.
E.g. mounting by

  sudo mkdir /mnt/fat
  sudo mount -o loop efi.img /mnt/fat

and inspection by

  find /mnt/fat

should list at least

  /mnt/fat
  /mnt/fat/efi
  /mnt/fat/efi/boot
  /mnt/fat/efi/boot/bootx64.efi


Fishy looking are:

> mcopy -i $BOOT_IMG -s $BOOT_IMG_DATA/efi ::

I cannot find any mcopy manual which mentions option -i.


> grub-mkimage \

There is no embedding of a config file to see (-c) and you put no .cfg
file into the efi.img. See
  
https://www.gnu.org/software/grub/manual/grub/html_node/Embedded-configuration.html

But EFI should not care about this and at least bring you to a GRUB prompt.
You could make a minimal grub-mkrescue image and compare the behavior of
both:
  mkdir minimal
  touch minimal/empty-file.txt
  grub-mkrescue -o output.iso minimal


Whatever, you will need a GRUB configuration.
Older Debian ISOs have embedded confgurations in their bootx64.efi and the
newer ones have a configuration file /efi/debian/grub.cfg in efi.img.
Both seem to make the connection to the GRUB stuff in the ISO
  search --file --set=root /.disk/info
  set prefix=($root)/boot/grub
  source $prefix/x86_64-efi/grub.cfg

But since you started by an ISO without any GRUB equipment, you will probably
not have it now.
You could copy it from a Debian ISO

  sudo mkdir /mnt/iso
  sudo mount -o loop debian-10.0.0-amd64-netinst.iso /mnt/iso
  find /mnt/iso/boot/grub | less

shows 264 lines. (boot/grub/efi.img is the EFI partition image, which you
will not need to copy.)
The content of the main .cfg file would have to be adapted to your needs:
  boot/grub/grub.cfg

But after you translated your ISOLINUX configuration to a GRUB configuration,
why struggeling with grub-mkimage and xorriso when you can let grub-mkrescue
do the job of controlling both ?
Manual:
  
https://www.gnu.org/software/grub/manual/grub/html_node/Invoking-grub_002dmkrescue.html
A bit more tangible:
  https://wiki.osdev.org/GRUB#ISO_instructions
One of the many toy operatings systems which use grub-mkrescue
  https://github.com/Nufflee/EPIC
  https://github.com/Nufflee/EPIC/blob/master/Makefile

The boot audience for grub-mkrescue is defined by the installed GRUB
architectures. Stuff like listed for BIOS, 64 bit EFI, 32 bit EFI in:
  https://packages.debian.org/sid/amd64/grub-pc-bin/filelist
  https://packages.debian.org/sid/amd64/grub-efi-amd64-bin/filelist
  https://packages.debian.org/sid/i386/grub-efi-ia32-bin/filelist

If you need help with installing GRUB for above targets or with converting
ISOLINUX configuration to GRUB, you may try this mailing list
  https://lists.gnu.org/mailman/listinfo/help-grub


Have a nice day :)

Thomas