Dual boot system with UEFI and Fedora 20 and Windows 8.1

In short sentences:

Yes it is possible! Even with secure boot enabled!

The long version:

On my workstation I use a dual boot configuration for some games and my Linux based development and testing. Since I am using a UEFI only configuration it was quite easy to use a dualboot configuration with Fedora 20 and Windows 8.1.

I turned off the legacy mode on my board and reactived the secure boot option I disabled some time ago for testing. The most UEFI boards should come with this options as their default values. Since I connected each system HardDisk/SSD seperated for installation, Fedora couldn't recognize the Windows disk and the boot menu entries automatically. This was just to protect my data since I am using two equal SSDs with the same size I didn't want to risk to select the wrong and loose all my data.

The Fedora disk is my first boot disk and I only added these lines to the grub.cfg located on the EFI partition (/boot/efi/EFI/fedora/grub.cfg) to add the Windows entry:

menuentry 'Windows Boot Manager' {
 set root='hd1,gpt2'
 chainloader /EFI/Microsoft/Boot/bootmgfw.efi
 boot
}

That's it. Reboot and test it. If everything is working as expected you should add this lines the correct way using /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# 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 Boot Manager' {
 set root='hd1,gpt2'
 chainloader /EFI/Microsoft/Boot/bootmgfw.efi
 boot
}

and run:

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