[Bug 1091464] Re: Unable to chainload Windows 8 and 10 with Secure Boot enabled

Chris Murphy 1091464 at bugs.launchpad.net
Tue Jun 18 16:41:10 UTC 2024


It does on Fedora.

The new problem though is computers with TPM 2 and Windows 10/11
preinstalled are frequently (and increasingly) coming with BitLocker
enabled. And the key is predicated on the boot chain being TPM
verifiable. By booting shim+grub first, it changes the measurements, and
Windows can't be unlocked without the large backup encryption key. But
if you use that key following a chainloaded boot, the new measurement
should be added by Windows to the TPM making subsequent chainloading
possible - but of course if you boot the Windows bootloader directly
(via UEFI boot manager menu) the measurement will be off again and boot
fails.

So it's important to have the BitLocker key available before starting
any installation.

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https://bugs.launchpad.net/bugs/1091464

Title:
  Unable to chainload Windows 8 and 10 with Secure Boot enabled

Status in grub2 package in Ubuntu:
  Fix Released

Bug description:
  I've been working with Yannubuntu and he suggested I post a bug here.
  Here's what I did.

  Received a brand new Dell XPS13 laptop with Windows8 pre-installed
  with both UEFI and SecureBoot enabled.    After playing around,
  decided to wipe everything and create a dual boot configuration with
  both Windows 8 and Ubuntu 12.10.  Steps:

  1. Install Windows 8 via Dell supplied recovery media in UEFI mode.  The installer will create the /boot/efi, recovery and main partition.  
  2. Use Windows 8 to resize hard drive down to 50GB.  Use the rest for Ubuntu.
  3. Verify the computer boots successfully to Windows 8 with UEFI and Secure Boot enabled.
  4. Boot with USB Ubuntu install media and select 'do something else' to create partitions and indicate /boot/efi
  5. Let the install complete.  Normally here, I run boot repair because the signed bootloader doesn't seem to install.  In boot repair, I use advance options, indicate where the EFI boot should go, primary OS (ubuntu) and select SecureBoot.
  6. Now, everything is configured as I want it.  Upon boot up, the computer will boot to grub and then I can go to either Ubuntu or Windows UEFI.  
  7. Upon selecting Windows UEFI, I get the error:

   /EndEntire
  file path: /ACPI(a0341d0,0)/PCI(2,1f)/UnknownMessaging(12)/HD(2,96800,32000,7c043777b8608641,87,f6)/File(\EFI\Microsoft\Boot)/File(bootmgfw.efi)/EndEntire
  error: cannot load image

  8.  If I swap the order in the BIOS to boot to Windows first (with UEFI and Secure Boot) it directly boots to Windows so I know the EFI boot files are working.
  9. If I go back to my original configuration (e.g. Ubuntu first) with UEFI, but Secure Boot disabled, then the system is able to successfully chainload the MSFT boot files.

  My gut tells me that grub is unable to chainload to an OS (or maybe
  just windows 8) which is expecting a secure boot to be initiated from
  the UEFI bios.

  As a work around, I have disabled Secure Boot, but I'd like my
  ultimate configuration to support Secure Booting to either Ubuntu or
  Windows 8 via grub.

  Thanks,

  Neeraj

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