[Bug 1061255] Re: GRUB recognizes defunct LDM headers

[Ronni]

I've reinstalled 12.04, out of curiosity.
Grub:
sudo apt-cache policy grub-pc
grub-pc:
  Installed: 1.99-21ubuntu3
  Candidate: 1.99-21ubuntu3
  Version table:
 *** 1.99-21ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

And the grub.cfg - booting perfectly into Win7 on the secondary disk.

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os {
        insmod part_msdos
        insmod ntfs
        set root='(hd1,msdos2)'
        search --no-floppy --fs-uuid --set=root 085AFE3C5AFE265A
        chainloader +1
}

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https://bugs.launchpad.net/bugs/1061255

Title:
  GRUB recognizes defunct LDM headers

Status in “grub2” package in Ubuntu:
  In Progress
Status in “grub2” source package in Quantal:
  In Progress

Bug description:
  [Impact]
  Grub can no longer boot Windows

  [Test Case]
  Use Windows to format a dynamic disk.  Use fdisk to repartition the disk as a regular MBR disk.  os-prober still recognizes the defunct ldm partition table with the Windows partition in it.

  [Regression Potential]
  Previously grub had no support for ldm, so the worst case is that it goes back to not recognizing ldm, as opposed to the goal of this patch of only recognizing *valid* ldm.
  .

  GRUB recognizes stale LDM headers left on the disk after reformatting
  without LDM.  This causes grub to complain either that embedding is
  not possible, and/or to incorrectly use the ldm partition module
  instead of msdos.

  - This bug affect GRUB2.00 (default bootloader of Ubuntu12.10).
  - This bug completely breaks access to any operating system, either when installing a fresh 12.10, or when upgrading from 12.04 to 12.10.

  ********************
  WORKAROUND1 (when GRUB appears, but the Windows entry fails and shows a "A disk Error Occurred" error):
  see Comment #44 below ( https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1061255/comments/44 )

  WORKAROUND2:
  see Comment #26 below ( https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1061255/comments/26 )

  WORKAROUND3:
  Use Boot-Repair ( https://help.ubuntu.com/community/Boot-Repair ) from liveCD to replace GRUB2 by GRUB Legacy: run Boot-Repair --> Advanced options --> GRUB options tab --> tick "GRUB Legacy" --> Apply

  ********************

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