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

[Steve McIntyre]

Hi Drasko!

On Wed, Apr 24, 2013 at 05:11:16PM +0200, Drasko DRASKOVIC wrote:
>Hi all,
>I experienced similar problem on an ASUS X20E1 with pre-installed
>Windows 8 image and UEFI.

...

>I tried replacing the entries by :
>
>menuentry "Windows (UEFI)" {
>   search --set=root --file /EFI/Microsoft/Boot/bootmgfw.efi
>   chainloader /EFI/Microsoft/Boot/bootmgfw.efi
>}
>
>That helped find `bootmgfw.efi` but went directly into Windows
>Recovery blue screen, saying that device is not connected and gving an
>error 0xc000000f.

OK...

>At least this confirms that Windows 8 bootloader was found, but the
>way it was executed was wrong.

...

>Finally, I found that solution escribed here worked fine :
>http://falstaff.agner.ch/2012/12/18/ubuntu-12-10-and-windows-8-with-secure-boot-mode/
>
>This script : https://gist.github.com/falstaff84/4330598/raw/adaf598a78d568dbfada596441bdfad3b4dd3f97/25_windows_uefi
>seem to be doing a job of broken `os-prober` and creates correct
>grub.cfg entry :
>
>### BEGIN /etc/grub.d/25_windows_uefi ###
>menuentry "Windows 8 (loader)" {
>	insmod search_fs_uuid
>	insmod chain
>	insmod part_gpt
>	insmod fat
>	set root='(hd0,gpt1)'
>	search --no-floppy --fs-uuid --set=root BA44-790F
>	chainloader /EFI/Microsoft/Boot/bootmgfw.efi
>}
>### END /etc/grub.d/25_windows_uefi ###
>
>It is similar as the workaround proposed in this bug earlier, but  I
>can notice two things here : UUID dieffers and adequate modules are
>inserted (like `fat` for example).
>
>I hope that this helps bug discovery and elimination.

It does help a little, thanks!

Based on what you have here and extra information and a
mostly-functional set of patches in

  https://lists.debian.org/debian-boot/2012/10/msg00185.html

I've built modified grub and os-prober packages. They work for me on
the (one!) Windows 8 UEFI machine I have available for testing. Could
you please try them and let me know if they work OK for you? They're
available for download from 

  http://www.einval.com/debian/efi/

along with the diffs I've used. If these work OK, I'm hoping we might
get the changes in before the Wheezy release. Without them, we're
going to get a lot of people reporting problems when installing
alongside Windows 8...

-- 
Steve McIntyre, Cambridge, UK.                                steve at einval.com
  Getting a SCSI chain working is perfectly simple if you remember that there
  must be exactly three terminations: one on one end of the cable, one on the
  far end, and the goat, terminated over the SCSI chain with a silver-handled
  knife whilst burning *black* candles. --- Anthony DeBoer