[Bug 1839317] Re: Grub fails to chainload the Windows Boot Manager on aarch64 laptops

[Steve Langasek]

The standard UEFI boot path for Ubuntu is always to boot via shim and
then to grub.

But we also know that the signed shim binary we currently have for arm64
is broken on this architecture.

The fixed shim is in the process of being signed and in the meantime
this is simply an unsupported configuration.

If this is reproducible when chainloading from shim to grub, then it is
a valid bug and requires further investigation.  But there are log
messages in the bug history suggesting that the lack of shim might be
the cause, so for the moment I am assuming that is the case and marking
this as invalid.

Given that you've mentioned having secureboot turned off anyway, you
could try the unsigned shim binaries from https://launchpad.net/~ubuntu-
uefi-team/+archive/ubuntu/ppa/+packages to see if you can reproduce the
problem when booting shim->grub.

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

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https://bugs.launchpad.net/bugs/1839317

Title:
  Grub fails to chainload the Windows Boot Manager on aarch64 laptops

Status in grub2 package in Ubuntu:
  Invalid

Bug description:
  After an update to 2.04 Grub fails to chainload into Windows.

  When selecting the menu item to boot into the Windows Boot Manager,
  the menu flashes and returns.

  When trying to chainload/boot via the Grub command line, nothing
  happens and the prompt reappears.

  When using the same commands in an earlier version (on a bootable USB
  stick) Windows sparks into life.

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