[Bug 995144] Re: Grub2 Corrupts Hard Drive and Bad Design Causing failed boot.

[Phillip Susi]

Installing grub to a partition requires that the core image file have
its sector list embedded in the MBR so it can be loaded, which comes
with its own set of problems, including failure if the file is moved by
a defragger, and getting block lists on some filesystems such as btrfs
is not even possible.  This is why such setups are unsupported by the
grub developers and so this will not be changed.

If you want grub to fit within the first 63 sectors of the disk, you
will need to use a simple boot setup, such as a plain ext2 /boot
partition, rather than more complex setups which simply requires more
code than can fit there.


** Changed in: grub2 (Ubuntu)
       Status: Confirmed => Won't Fix

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https://bugs.launchpad.net/bugs/995144

Title:
  Grub2 Corrupts Hard Drive and Bad Design Causing failed boot.

Status in “grub2” package in Ubuntu:
  Won't Fix

Bug description:
  It's bad enough that the designers of various linux distros decided
  the default place for GRUB was the MBR instead of adhering to standard
  PC architecture practices (which all other OSes, including *nix
  version, followed), of putting the kernel loaders in the partition and
  making it active so standard code in the MBR would transfer control to
  it.  For cases where a volume was to boot it could have made the
  Extended partition active, put the start code in the EBR of the
  extended and have that boot the volume.    The Linux community would
  have a fit if MS decided it was going to write its own kernel loaders
  and stick them in the MBR and take over the disk.

  Anyway, now apparently whoever has taken over GRUB2 (latest version)
  has made some big mistakes and must not understand the standard pc
  architecture either.  Someone has made it write outside the first
  track of the hard drive if it doesn't think there is a partition
  there.

  1 - Writing outside the first track of the hard drive can corrupt
  partitions not in the MBR at the time which is common with various
  partitioning schemes and cause data loss for users.

  2 - Adding a partition to the start of the disk (cylinder aligned)
  afterwards would overwrite the part of GRUB written out beyond the
  first track making the entire system unbootable.

  3 - changing partition layouts can again overwrite GRUB data which
  should be in the partition by default.

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