sudo grub-install  /dev/sda
Searching for GRUB installation directory ... found: /boot/grub
Installing GRUB to /dev/sda as (hd0)...
Installation finished. No error reported.
This is the contents of the device map /boot/grub/device.map.
Check if this is correct or not. If any of the lines is incorrect,
fix it and re-run the script `grub-install'.

(hd0)   /dev/sda
(hd1)   /dev/sdb