Ubuntu
grub2 package

  1. Bug #807801
  2. Comment #7

Comment 7 for bug 807801

Revision history for this message
Rasmus Pedersen (rasmuslp) wrote : Re: grub-update fails to detect windows bootloader on a uefi system

I have solved this temporarily.

The GRUB menu can be unhidden by commenting out the two lines regarding GRUB_HIDDEN in /etc/defaults/grub and running update-grub as root.

Next, the entry for windows can be manually added by appending the following lines to /etc/grub.d/40_custom:
menuentry "Windows" {
    search --fs-uuid --no-floppy --set=root YOUR-EFI-PARTITIONS-UUID-HERE
    chainloader (${root})/efi/Microsoft/Boot/bootmgfw.efi
}

Find your EFI partitions UUID by running 'ls -la /dev/disk/by-uuid/'. As the EFI partition is a FAT32 partition, the UUID is of the form XXXX-XXXX. If you have more than one FAT partition, you can verify if one is the EFI partition by checking the partition map with gdisk (not installed by default). Run gdisk on the device, 'sudo gdisk /dev/DEVICE', press 'p' to print the partition table, and then 'q' to quit. DON'T make any changes to the partition table. The EFI partition will have the code type 'EF00' and most likely a name/label that says it is a EFI system partition.