os-prober wrongly switches recovery and Vista partitions

[Chow Loong Jin]

  affects ubuntu/os-prober
  status triaged
  affects ubuntu/maverick/os-prober

Upon a fresh install of Ubuntu on a dual boot machine, I have found that the
GRUB entries for Windows Vista and Windows Recovery something or other were
switched, i.e. booting into "Windows Vista" caused the recovery partition to
load, and vice versa.

This problem is not rare, as shown by this thread:
http://ubuntuforums.org/showthread.php?t=1513576

Upon digging into /usr/lib/os-probes/mounted/20microsoft, I found that the check
grep'd for "Windows Recovery Environment" in the BCD of each Windows
installation found (if BCD existed). However, I presume that on an OEM Windows
installation, an entry for "Windows Recovery Environment" would be already added
to the installation of Windows, hence causing it to be wrongly detected as a
recovery partition instead.

Incidentally, the recovery partition itself did not have "Windows Recovery
Environment" found in its BCD file.

Upon running strings -e l $bcdfile on each of the partitions BCD files, I have
found that the recovery partition has a string "Windows Setup", which is not
present in the other, and the Vista installation had the string "Windows Vista"
in its BCD which was not present in the other either.

Hence I propose this patch be applied to the 20microsoft checker script of
os-prober.

I have not tested this on any other setup apart from the machine I just
installed Ubuntu onto, which seems to be a "eMachines D620".

--
Kind regards,
Loong Jin