Fedora Windows Dualboot Uefi

On my Lenovo IdeaPad Yoga I have a dualboot installation with Windows 8 and Fedora 18. My setup works fine with UEFI, however I'd prefer to boot Windows 8 out of grub. So here is a small tutorial on how to add your windows installation to grub.

1. Install the following packages:

sudo yum install grub2-efi os-prober shim

Your UUID

Your first step is to find out the right UUID for the Windows partition. One way to do this is:

sudo gdisk -l /dev/sda

Then you should see something like this:

Number Start (sector) End (sector) Size Code Name
1 2048 616447 300.0 MiB 2700 Basic data partition
2 616448 821247 100.0 MiB EF00 EFI system partition
3 821248 1083391 128.0 MiB 0C01 Microsoft reserved part
4 1083392 204802047 97.1 GiB 0700 Basic data partition
5 204802048 205211647 200.0 MiB EF00 EFI System Partition
6 205211648 206235647 500.0 MiB 0700
7 206235648 222357503 7.7 GiB 8200
8 222357504 327215103 50.0 GiB 0700
9 327215104 500117503 82.4 GiB 0700

In my case the Windows EFI partition is the first one, but if you are not sure, you can mount the EFI system partition and look if 'tree' prints out this:

.
└── EFI
├── Boot
│ └── bootx64.efi
└── Microsoft
└── Boot
├── BCD
├── BCD.LOG
├── BCD.LOG1
├── BCD.LOG2
├── bg-BG
│ ├── bootmgfw.efi.mui
│ └── bootmgr.efi.mui
├── bootmgfw.efi
├── bootmgr.efi
├── BOOTSTAT.DAT
├── boot.stl
...

Now it's time to get the UUID of this partition. You can do this with:

sudo blkid /dev/sda2

This gives you something like:

/dev/sda2: UUID="B8EA-3088" TYPE="vfat" PARTLABEL="EFI system partition" PARTUUID="9c0c3f2e-82a2-428d-9366-90f8c4580652"

Update your grub config

You can now add your UUID to grub. Edit /etc/grub.d/40_custom and add the following lines. Replace "your_UUID" with the UUID from the previous step.

menuentry "Windows" {
  insmod part_gpt
  insmod fat
  insmod search_fs_uuid
  insmod chain
  search --fs-uuid --no-floppy --set=root your_UUID
  chainloader (${root})/efi/Microsoft/Boot/bootmgfw.efi
}

The Rebuild

And finally you can rebuild the config with:

grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg