grub-reboot

Set the default boot entry for GRUB, for the next boot only. More information: https://manned.org/grub-reboot.

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

sudo grub-reboot entry_number

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

sudo grub-reboot --boot-directory /path/to/boot_directory entry_number