I have just installed KaOS on a machine that already had three other systems installed. I am looking for a Plasma-centered Linux and thus, beside Windows 10, I have installed Kubuntu 20.04, Fedora 34 KDE, and then KaOS. Thus KaOS is the last installed and its boot menu is shown when powering on the laptop. (In the end I will renounce some of those but for some time I want to keep them all for testing Plasma.) I have used such multiple configuration in the past but mostly on MBR drive structure, while the present installations are all UEFI.
There are two drives. One contains the Windows 10 partitions, the Kubuntu partition, the KaOS partition (
nvme0n1p7) and a EFI partition shared by Windows 10 and Kubuntu .
The second drive contains the Fedora partitions, two non-system partitions for storage and an EFI partition (
sda1) shared by Fedora and KaOS (although KaOS is installed on the other drive ; this odd choice is related to the fact that past installation of a second Linux, beside Kubuntu, using the same EFI as Windows, has resulted in corruption of Windows boot; that was fixed by re-installing Kubuntu which added Windows to its boot menu; I wanted to avoid such interference with Windows and therefore I have set KaOS to use the EFI partition from the other drive, the one shared with Fedora).
All three Linux systems use grub for their boot menu.
Device Start End Sectors Size Type
/dev/nvme0n1p1 2048 739327 737280 360M EFI System
/dev/nvme0n1p2 739328 1001471 262144 128M Microsoft reserved
/dev/nvme0n1p3 1001472 457750527 456749056 217,8G Microsoft basic data
/dev/nvme0n1p4 457750528 459757567 2007040 980M Windows recovery environment
/dev/nvme0n1p5 459757568 500107263 40349696 19,2G Microsoft basic data
/dev/nvme0n1p6 500107264 644737022 144629759 69G Linux filesystem
/dev/nvme0n1p7 644737023 976773134 332036112 158,3G Linux filesystem
Device Start End Sectors Size Type
/dev/sda1 2048 1230847 1228800 600M EFI System
/dev/sda2 251660288 1258293247 1006632960 480G Linux filesystem
/dev/sda3 1258293248 1875384319 617091072 294,3G Microsoft basic data
/dev/sda4 1230848 3327999 2097152 1G Linux filesystem
/dev/sda5 3328000 251660287 248332288 118,4G Linux filesystem
When I start the laptop I see the KaOS boot menu containing only KaOS and the firmware menu option. If I select firmware I can then access separately the Fedora and the Ubuntu boot menus, each of them containing the other systems, including KaOS (excepting the Kubuntu boot menu which lacks Fedora for some reason).
sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/initramfs-linux.img
Found fallback initramfs image: /boot/initramfs-linux-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Windows Boot Manager on /dev/nvme0n1p1@/efi/Microsoft/Boot/bootmgfw.efi
Found Ubuntu 20.04.3 LTS (20.04) on /dev/nvme0n1p6
Adding boot menu entry for UEFI Firmware Settings ...
Thus, Windows and Ubuntu are detected here — while Fedora is not! It seems to me
os-prober is looking for bootable partitions only on the drive with its system partition (
/dev/nvme...) and not at all on the other (
But even so the boot menu is not changed at all. No other system is added beside KaOS
Could I add the other systems to the KaOS boot menu? - Or is it normal for the other systems to just be accessible from firmware/BIOS settings? - I would find that odd, given I think grub is used by all Linux systems here and the others show (almost) all the rest. e.g. before installing KaOS the laptop used to start with a (Fedora boot menu) screen showing me all the systems, the menu was even themed by me etc.
(Or, if KaOS boot menu is not editable, how could I make the computer show directly the Fedora boot menu which contains all entries?)