Unable to use grml-rescueboot to boot live image from harddrive on 22.04

Hi. I recently upgraded from UB 20.04 to 22.04 on my HTPC and this morning I installed grml-rescueboot to boot live images from the harddrive. The install worked fine, I added 3 ISO images into the /boot/grml folder (each one a Ubuntu-based distro), ran update-grml from the terminal and it showed the ISO images that I had added. When I reboot however, there is no boot menu showing the added options to load these ISO images. Instead, the system just boots straight into the installed UB 22.04 as it did before I installed the grml software. Any idea why there’s no boot menu appearing? Thanks.

Nevermind. I figured it out. I just needed to edit the file /etc/default/grub, changing “hidden” to “menu” and setting the timeout to 10 seconds.