[Bug 1845289] Re: Grub EFI amd64 no longer start EFI/Microsoft/Boot/bootmgfw.efi

[Mathieu Trudel-Lapierre]

No; this patch is wrong.

For starters, you really ought to have shim installed, and that is the
primary cause for such failures -- somehow your install is incomplete,
and shim was removed either because the package was removed, or through
the use of boot-repair (IIRC it replaces shim with using grub directly,
which is not supported).

Then, the code for the chainloader already is supposed to handle Secure
Boot being off -- if it's disabled, the linuxefi_secure_validate()
function sees that and returns 1 (image is deemed valid, since SB is
disabled). Then we run grub_secureboot_chainloader_boot(), which will
execute handle_image(), which should immediately check read_header() and
find out, again, whether Secure Boot is enabled and/or if shim is
available; returning with whatever status was retrieved reading the
header for the binary that is to be chainloaded.

I'd expect that if Secure Boot is not enabled, you would again have a
return code of 0 there, and move on to using the normal chainload
behavior of load_image and start_image.

Please, if you're running into this issue, try stopping at the grub
menu, and edit the chainload entry to add:

set debug="chain"

At the top, taking a screenshot or video of the boot process that you
can then attach here. We really need to know if this is caused by one
unusually built binary, or what precisely is going on before making any
patches to GRUB.

** Changed in: grub2 (Ubuntu)
       Status: Confirmed => Incomplete

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https://bugs.launchpad.net/bugs/1845289

Title:
  Grub EFI amd64 no longer start EFI/Microsoft/Boot/bootmgfw.efi

Status in grub2 package in Ubuntu:
  Incomplete
Status in grub2 source package in Eoan:
  Confirmed

Bug description:
  On a dual boot computer with Windows 10 Pro and Ubuntu 19.10, since a
  month, Grub was unable to boot Windows 10. Hitting the Windows entry
  line give me a 0.1s black screen and get me back to Grub Menu.

  sudo update-grub give me :

  Sourcing file `/etc/default/grub'
  Sourcing file `/etc/default/grub.d/init-select.cfg'
  Generating grub configuration file ...
  Found linux image: /boot/vmlinuz-5.3.0-10-generic
  Found initrd image: /boot/initrd.img-5.3.0-10-generic
  Found Windows Boot Manager on /dev/sda1@/EFI/Microsoft/Boot/bootmgfw.efi
  Adding boot menu entry for EFI firmware configuration
  done

  ProblemType: Bug
  DistroRelease: Ubuntu 19.10
  Package: grub-efi-amd64 2.04-1ubuntu5
  ProcVersionSignature: Ubuntu 5.3.0-10.11-generic 5.3.0-rc8
  Uname: Linux 5.3.0-10-generic x86_64
  ApportVersion: 2.20.11-0ubuntu7
  Architecture: amd64
  CurrentDesktop: ubuntu:GNOME
  Date: Wed Sep 25 08:01:05 2019
  ProcEnviron:
   TERM=xterm-256color
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=fr_FR.UTF-8
   SHELL=/bin/bash
  SourcePackage: grub2
  UpgradeStatus: Upgraded to eoan on 2018-11-14 (314 days ago)

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