We have now completed steps 1 to 6 as outlined in Chapter 2, Building the 5.x Linux Kernel from Source – Part 1, in the Steps to build the kernel from source section). We can reboot the system; of course, do first close all your apps and files. By default, though, the modern GRUB (GRand Unified Bootloader) bootloader does not even show us any menu on reboot; it will by default boot into the newly built kernel (do remember that here, we're describing this process only for x86[_64] systems running Ubuntu).
What if we would like to see and customize the GRUB menu every time we boot the system, thus allowing us to possibly select an alternate kernel/OS to boot from? This is often very useful during development, so let's find out how we can do this.
