how to get grub to boot other partition


I have installed OpenSuse Tumbleweed (64bits) on an ‘old’ Dell D830 laptop. It runs Server/Command line only.

The machine has one disk: sda with the following partitions:
sda1 - bios grub
sda2 - swap
sda3 - / (btrfs filesystem) ← this is where opensuse lives.
sda4 - (ext4 filesystem, already resize2fs’d to 32 bit.) <— this is where l have created a linux from scratch environment

The diskpartitioning is based on gpt

The current grub2 config is still as it was initially installed.

Searching forums and documentation on line as to how to get this machine to boot from either sda3 or sda4 has not helped me any further. Reading grub config files in /boot and /etc/syslinux the create a lot of clarity either for the last few hours I’ve looked into this.

Who can point me in the right direction with this?

Sorry for my lack of grub skills.


Hi Berrie,

My approach to this is at the command line prompt as root: (or sudo the commands, if preferred)

  1. cd /boot/grub2
  2. cp grub.cfg grub.cfg.bkcp
    [This makes a backup of existing boot menu file]
  3. grub2-mkconfig -o grub.cfg
    This command will rescan hard drives and add entries to new grub.cfg for “found” bootable partitions.