How-to: Install Grub on a several disk.
Install Grub on several disks, for example, if there is no more space on the primary hard disk or for other reasons.
Step 1: Reconfigure grub
With a dpkg-reconfigure you could you can perform the configuration again.
dpkg-reconfigure -plow grub-pc
Step 2: Choose the storage
If preconfigured files are available, these can be accepted with “Ok” using the Tab and Return keys.
The correct storage can be selected with the Arrow keys and the Space key, then confirm the installation again with Tab and Return.
For example, it would look like this:
1st. Picture
2nd. Picture
Step 3: Reboot the system
After the reconfigure is successfully done, just reboot the whole system.
reboot