How to reinstall Grub 2 to master boot record
https://answers.launchpad.net/me-tv/+question/79735
GRUB
Using Ubuntu livecd
Here assuming the Ubuntu partition is sda7 and /boot partition is sda6 (if you have a separate /boot partition).
Boot up ubuntu from the livecd, open terminal and run:
sudo -i
mount /dev/sda7 /mnt
mount /dev/sda6 /mnt/boot #skip this one if not have a separate /boot partition
grub-install --root-directory=/mnt/ /dev/sdaIf you miss grub.cfg file,use following to recreate:
mount --bind /proc /mnt/proc
mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
chroot /mnt update-grub
umount /mnt/sys
umount /mnt/dev
umount /mnt/proc
exitUsing the cd/usb boot up with GRUB
Boot up the CD/USB, press “c” in grub menu. Type:
find /boot/grub/core.img
root (hdx,y) (previous command will output the x,y)
kernel /boot/grub/core.img
bootAfter the boot command,you’ll go into GRUB 2 menu. Select to boot up Ubuntu and run this command to restore GRUB:
sudo grub-install /dev/sda
How to add Vista/Windows 7 partition to Grub 2
sudo fdisk -l /dev/sda
According to this my Windows partition is hda1. To continue with my plan to add Windows boot option I typed in the following line:
sudo nano /etc/grub.d/11_Windows
This created a new a new file. I then added the following lines:
#! /bin/sh -e
echo "Adding Windows" >&2
cat << EOF
menuentry "Windows 7" {
set root=(hd0,1)
chainloader +1
}
EOFNow save the 11_Windows file.
Bare in mind that in earlier version of GRUB, if your Windows was installed on first partition then you need to give root=(hd0,0). Thats how GRUB used to number partitions. Starting from GRUB 2, you need to give root=(hd0,1), if your Windows is installed on first partition. So under GRUB 2 it looks like this:
First partition (/dev/sda1): root=(hd0,1)
Next type the following command:
sudo chmod a+x /etc/grub.d/11_Windows
Next type in the following command:
sudo update-grub
You should be able to see something like this:
# sudo update-grub
Generating grub.cfg
Found linux image: /boot/vmlinuz-2.6.30-9-generic
Found initrd image: /boot/initrd.img-2.6.30-9-generic
Found linux image: /boot/vmlinuz-2.6.30-8-generic
Found initrd image: /boot/initrd.img-2.6.30-8-generic
Adding Windows
Found memtest86+ image: /boot/memtest86+.bin
doneNow close all the open programs and type in the following command to your terminal:
sudo reboot
If all went well you should see Windows 7 option in your GRUB2.
