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**INVICTRA** · Apr 25, 2026, 06:38 PM

Yes that looks OK. Should work. Follow AI suggestion.
After you got everything installed then make a backup of the boot partition (ESP) with something like KDE Partition Manager. Because Windows might delete it and recreate it in certain scenarios (Big update, FIX boot etc.). I find it faster to just restore a ESP that windows ****ed up than using live CD to repair Linux boot.

**jlittle** · Apr 25, 2026, 07:27 PM

Originally posted by zahtar View Post

install Vanilla, then Kubuntu so I keep the Kubuntu boot loader.

(You'll want to turn on grub's OS prober, by setting GRUB_DISABLE_OS_PROBER=false in /etc/default/grub and running update-grub.)

Some Vanilla update might still trample on the kubuntu boot loader. If Vanilla uses grub, you could uninstall it from Vanilla to stop that. Being familiar with sudo efibootmgr could be useful.

I don't know how Vanilla installs to a btrfs; if it uses subvolumes you could put it and Kubuntu in the same btrfs to economize on space, with some /etc/fstab and grub manipulation.

**zahtar** · 2026-05-01T20:15:58

Hello, thank you both for your replies!

I installed Vanilla, it went well up to that point, with the exception that it asked to ¨keep EFI¨ in case I multi-boot, with the result not prioritizing its boot loader. From that point on, I needed to press F12 to get the boot menu, where vanilla was available and would boot properly if selected. Otherwise, the laptop used to boot to win11.

I thought this would not be a big deal, since I was ready to install kubuntu and expected its bootloader to take care of things. But this did not happen. The Vanilla option still doesn´t show up in grub, I still need to access the OS by F12 during power up. If I let it boot, grub will just show entries like ¨kubuntu, windows boot loader, UEFI hardware settings¨. This is after entering sudo update-grub

The weird thing is that when running sudo update-grub (I did that twice), the system does detect vanilla, promises that it will update the grub entry, but it doesn´t...

So, two questions:
a) Is there another way to edit grub entries so I get all options in grub? Or make the system properly update the entries automatically?
b) During installation, I didn´t tell kubuntu to use the /EFI partition that I created for Vanilla. I created another one so the new labels and flags cause no errors. Is this ok?

PS: if this conversation needs to move to a post-installation thread, let me know and I´ll rephrease here and create a new one.

**jlittle** · 2026-05-02T07:34:22

Originally posted by zahtar View Post

a) Is there another way to edit grub entries so I get all options in grub?

There's at least 3 ways to do this:

edit the file /etc/grub.d/40_custom to have the menu entries you need, then run sudo update-grub,
create the file /boot//grub/custom.cfg with the desired entries; no update-grub needed.
eschew the whole update-grub machinery altogether, and maintain manually grub.cfg.

No. 3 is a big step but I have done it for years and I claim that it's easier and far more reliable in the long term.

With any of these methods menu entries for a *buntu install can look like this:

Code:

menuentry 'Kubuntu' --class ubuntu --class gnu-linux --class gnu --class os {
    search --no-floppy --label --set=root your-label

    linux /@/boot/vmlinuz root=LABEL=your-label ro rootflags=subvol=@
    initrd /@/boot/initrd.img
}

Adjust your-label to suit. More conservatively you can use the UUID instead; change --label to --fs-uuid and LABEL to UUID, and put in the UUID instead of the label, twice.

Or make the system properly update the entries automatically?

Note that entries like the above boot the latest kernel and initrd ("initial ram disk') so don't have to be updated when a new kernel arrives. I have gone years without needing to touch an entry.

**barfly** · 2026-05-02T09:09:08

Laptops have many different keys for accessing the bios, but the majority use either F2 or F8. This is not the same as a temporary F12 to get a drop-down list of bootable options.

You need to get into the bios proper, and there will be an option for permanently selecting the correct (for you) o/s to be your primary boot system. Then reboot and you should the boot straight into your flavour of choice without having to press the F12 key for the drop-down boot menu.

Cheers Tony

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Manual partitioning advice for multiboot with Kubuntu 26.04LTS and two more OSs.

[Pre-Install] Manual partitioning advice for multiboot with Kubuntu 26.04LTS and two more OSs.

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