Bug#698914: grub-efi booting Windows 8 in UEFI mode

[Steve McIntyre]

Package: grub-efi
Version: 1.99-26
Severity: important

Hi,

On a new machine that came pre-configured with UEFI and Windows 8
(Lenovo G580), I've installed Debian dual-boot and grub-efi works well
for booting that Debian system. However, the menu entries created for
Windows on this machine (the primary Windows installation and the
recovery partition) both fail to boot with the same message:

  error: unknown command `drivemap'.
  error: invalid EFI file path.

  Press any key to continue...

The grub.cfg entries for these are:

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows Recovery Environment (loader) (on /dev/sda3)" --class windows --class os {
        insmod part_gpt
        insmod fat
        set root='(hd0,gpt3)'
        search --no-floppy --fs-uuid --set=root 4411-65A9
        drivemap -s (hd0) ${root}
        chainloader +1
}
menuentry "Windows 8 (loader) (on /dev/sda5)" --class windows --class os {
        insmod part_gpt
        insmod ntfs
        set root='(hd0,gpt5)'
        search --no-floppy --fs-uuid --set=root A48815AD88157ECC
        drivemap -s (hd0) ${root}
        chainloader +1
}
### END /etc/grub.d/30_os-prober ###

I'm guessing "drivemap" isn't a valid thing in grub-efi and this would
work in BIOS mode?

Based on information found from a web search, I've added by hand an
extra stanza to load the main Windows 8 entry in UEFI mode:

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "Windows (UEFI)" {
   search --set=root --file /EFI/Microsoft/Boot/bootmgfw.efi
   chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/40_custom ###

and this works flawlessly for me. I don't know how easy this would be
to integrate into os-prober; does that know that it's running on an
EFI system at all?

It would be lovely to get this sorted for Wheezy... :-)

-- System Information:
Debian Release: 7.0
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.2.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages grub-efi depends on:
ii  grub-common     1.99-26
ii  grub-efi-amd64  1.99-26

grub-efi recommends no packages.

grub-efi suggests no packages.

-- no debconf information