[Bug 1024383] Re: update-grub generates only BIOS based menu entries for Windows, even on UEFI systems

[YannUbuntu]

> At update-grub time, you know if you are EFI and should search for an
EFI bootable windows.

No, don't rely on the mode where grub-update is used ! 
Counter-examples:
1) Windows is installed in UEFI mode but update-grub is used from a Ubuntu32bit liveCD (which cannot be booted in UEFI mode, see Bug #1025555 ).
2) Windows is installed in UEFI mode, but update-grub is used from a Legacy mode live-session because the BIOS is set up to boot the CD/USB in Legacy mode
3) Windows is installed in Legacy mode, but update-grub is used from an UEFI mode live-session because the BIOS is setup to boot the CD/USB in UEFI mode.

> an EFI booting system can't have a bios booting windows install.

I am nearly sure of the contrary, because many preinstalled Windows come with both files to be booted in UEFI and Legacy modes.
Examples: http://paste.ubuntu.com/1495850, http://paste.ubuntu.com/1479512 , http://paste2.org/p/2700549

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https://bugs.launchpad.net/bugs/1024383

Title:
  update-grub generates only BIOS based menu entries for Windows, even
  on UEFI systems

Status in “grub2” package in Ubuntu:
  Confirmed
Status in “os-prober” package in Ubuntu:
  Confirmed
Status in “grub2” package in Debian:
  New

Bug description:
  64bits computer with pre-installed EFI Windows 7. (remark: same bug if
  Windows8)

  Installed Ubuntu 64bits in dual-boot. GRUB (grub-efi) is correctly
  installed and allows to boot Ubuntu, but it does not allow to boot
  Windows.

  Its menu shows 2 INVALID Windows entries. When selecting these
  entries, it displays "Invalid EFI file path" error, and returns to
  GRUB menu.

  It appears that GRUB creates BIOS/mbr entries when it should be
  UEFI/gpt type entries.

  *********************** WORKAROUND **************************

  either boot Windows from the (EFI) BIOS menu, or add valid Windows entries via Boot-Repair.
  ***************************************************************

  (original thread in French: http://forum.ubuntu-
  fr.org/viewtopic.php?pid=10010231#p10010231 )

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