[Bug 1062737] Re: hybrid images do not include a valid GPT

[Thomas Schmitt]

Hi,

i closed this bug report because the libisofs fix is released since
nearly four years.

Summary of remaining issue:

The isohybrid layout as defined for ISOLINUX bootable ISO 9660 images
regularly works by the MBR partition of type 0xef, not by the GPT partition 
which carries the type UUID of EFI System Partition.
This is well compliant to UEFI specs. E.g. UEFI 2.4, 5.2.1 "MBR".
Under these specs, the GPT and its backup are just opaque bytes of no
special meaning to UEFI, because the MBR is not "Protective".

GRUB2 program grub-mkrescue on the other hand lets xorriso create a 
Protective MBR and a valid GPT with a partition entry which marks the 
EFI System Partition.

Have a nice day :)

Thomas


** Changed in: libisofs (Ubuntu)
       Status: Triaged => Fix Released

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https://bugs.launchpad.net/bugs/1062737

Title:
  hybrid images do not include a valid GPT

Status in Ubuntu CD Images:
  Fix Released
Status in libisofs package in Ubuntu:
  Fix Released

Bug description:
  The insyde UEFI firmware implementation does not see the GPT on the
  hybrid images generated on nusakan (e.g., the 12.10 beta2 image).
  This appears to be consistent with what both gdisk and parted show:

  $ gdisk -l ~/devel/iso/ubuntu-12.10-beta2-desktop-amd64.iso 
  GPT fdisk (gdisk) version 0.8.5

  Partition table scan:
    MBR: MBR only
    BSD: not present
    APM: not present
    GPT: not present

  
  ***************************************************************
  Found invalid GPT and valid MBR; converting MBR to GPT format.
  ***************************************************************

  Disk /home/vorlon/devel/iso/ubuntu-12.10-beta2-desktop-amd64.iso: 1548288 sectors, 756.0 MiB
  Logical sector size: 512 bytes
  Disk identifier (GUID): 1ADDF8C9-5CE1-41A4-9124-2CC80EED991F
  Partition table holds up to 128 entries
  First usable sector is 34, last usable sector is 1548254
  Partitions will be aligned on 2048-sector boundaries
  Total free space is 1548221 sectors (756.0 MiB)

  Number  Start (sector)    End (sector)  Size       Code  Name
  $

  Removing the -partition_offset 16 option from the xorriso commandline
  is sufficient to generate an image with a recognizable partition
  table; but I imagine this causes other problems for hybrid systems.

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