Hi, originally my machine was a dual boot machine booting Windows 10 and Ubuntu 20.04. When I installed Ubuntu it was kind enough to create a nice menu I could use to select either Windows or Ubuntu to load at boot. I then created a partition and installed Qubes which seemed to work as I can now boot into Windows, Ubuntu and Qubes. However, Qubes wasn’t kind enough to create a nice menu option in the original boot menu and I have to press esc at boot and manually select the Qubes option at boot. It would be nice if somebody might know how I could add Qubes as an option to my nice grub menu.
I am not sufficiently knowledgeable to answer, but Qubes dom0 is based on Fedora 32, so you should be able to find the solution for Fedora-32 and apply it here.
I’m no expert on grub menus, but it seems to me that you would have to manage the grub menu from within Qubes by copying the current settings into the Qubes system and let it regenerate the grub menu as needed. When a new Qubes update comes through the system will automatically update the menu by regenerating the /boot and grub config info thus rewriting what is currently there on the boot partition. To generate it manually you do something like this:
Edit /etc/default/grub and make your mods.
If you use BIOS boot:
dom0> grub2-mkconfig -o /boot/grub2/grub.cfg
Or if you use UEFI boot:
dom0> grub2-mkconfig -o /boot/efi/EFI/qubes/grub.cfg
So all the current settings for Win and Ubuntu would likely go in `/etc/default/grub’ before regenerating everything. Do make backups before doing any of this because you may get a nonbootable system if there are any syntax errors in the grub config file. Learn and practice how to boot in recovery mode first.
I suggest you read the grub docs to see what parameters need to be set for the various menu entries. Its been way too long since I played with this stuff, so hopefully someone with a more current understanding will chime in to clarify things I may have missed.