How to Repair Grub on Fedora

1. Boot Your Fedora Live DVD/CD/USB

2. Open terminal

3. Check the partition list, use :

sudo fdisk -l

4. Mount Your root partition at /media, assuming is /dev/sda3

sudo mount /dev/sda3 /media

5. then, re-install Grub

sudo grub2-install --root-directory=/media /dev/sda

6. Update grub

sudo grub2-mkconfig -o /media/grub2/grub.cfg

7. You will have to adjust for your actual layout.