grub-set-default

Set the default boot entry for GRUB. More information: https://manned.org/grub-set-default.

• Set the default boot entry to an entry number, name or identifier:

sudo grub-set-default entry_number

• Set the default boot entry to an entry number, name or identifier for an alternative boot directory:

sudo grub-set-default --boot-directory /path/to/boot_directory entry_number