======Fedora 22 fix dualboot with Windows======
Sometimes Windows update destroys grub! When you boot you will get the grub commandline interface

Boot Fedora:
  grub> set root=(lvm/system-root)
  grub> linuxefi (lvm/system-boot)/vmlinuz-... root=/dev/system/root
  grub> initrdefi (lvm/system-boot)/initramfs-...
  grub> boot

In Fedora:

/dev/sda2 is /boot/efi
  mount -o remount,rw /dev/sda2
  grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Do a reboot afterwards
{{tag>linux}}