[Bug 1691505] [NEW] os-prober doesn't see Windows installations in an EFI system

[DiegoRivera]

Public bug reported:

On a multiboot installation of Ubuntu Yakkety and Windows using UEFI,
everything was working properly.  Upon update to Zesty, os-prober was
unable to locate the Windows partition and thus Grub
(2.02~beta3-4ubuntu2 and previous Zesty versions) wasn't generating the
correct bootable entries for it.

I edited /usr/lib/os-probes/mounted/efi/20microsoft to fix the issue by
updating it to the latest GRUB's expectations.  The original script only
output 3 columns: the device name, the label, and "Windows".  GRUB was
expecting 4 columns: the device name + EFI path (separated with @), the
label, "Windows", and "efi".

The script needed to be modified to properly handle these changes.  I'm
attaching the updated script, which works with both giving the device
name and the EFI mount path, producing what I believe to be the correct
output for both.

This updated prober script fixes the issue by correctly chaining to the
Windows boot manager.

OS-prober also has an issue where the scripts in the "efi" directory
(/usr/lib/os-probes/mounted/efi) aren't called, but instead need to be
"moved" (copied) into the parent directory.  This is a gap that needs
bridging (i.e. make os-prober also run those scripts automatically).

The expectation is that running "update-grub" would result in all
available boot options being detected and accounted for as per what grub
supports. Clearly that wasn't happening until the aforementioned script
was fixed and placed in the right location.

Cheers!

** Affects: os-prober (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: dual-boot grub os-prober windows

** Attachment added: "20microsoft"
   https://bugs.launchpad.net/bugs/1691505/+attachment/4878388/+files/20microsoft

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https://bugs.launchpad.net/bugs/1691505

Title:
  os-prober doesn't see Windows installations in an EFI system

Status in os-prober package in Ubuntu:
  New

Bug description:
  On a multiboot installation of Ubuntu Yakkety and Windows using UEFI,
  everything was working properly.  Upon update to Zesty, os-prober was
  unable to locate the Windows partition and thus Grub
  (2.02~beta3-4ubuntu2 and previous Zesty versions) wasn't generating
  the correct bootable entries for it.

  I edited /usr/lib/os-probes/mounted/efi/20microsoft to fix the issue
  by updating it to the latest GRUB's expectations.  The original script
  only output 3 columns: the device name, the label, and "Windows".
  GRUB was expecting 4 columns: the device name + EFI path (separated
  with @), the label, "Windows", and "efi".

  The script needed to be modified to properly handle these changes.
  I'm attaching the updated script, which works with both giving the
  device name and the EFI mount path, producing what I believe to be the
  correct output for both.

  This updated prober script fixes the issue by correctly chaining to
  the Windows boot manager.

  OS-prober also has an issue where the scripts in the "efi" directory
  (/usr/lib/os-probes/mounted/efi) aren't called, but instead need to be
  "moved" (copied) into the parent directory.  This is a gap that needs
  bridging (i.e. make os-prober also run those scripts automatically).

  The expectation is that running "update-grub" would result in all
  available boot options being detected and accounted for as per what
  grub supports. Clearly that wasn't happening until the aforementioned
  script was fixed and placed in the right location.

  Cheers!

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