What is the best way to create a multiboot with Ubuntu, Qubes and Windows?

User Support General
1

I see this guide but 1) it’s a bit more advanced than what i can grasp. For example it starts with the following straight out the gate:

If you have had to change to legacy boot mode then you may have to reinstall grub in the existing OS. (Make sure that you use grub rather than a grub-efi version).

Micah Lee suggests installing grub to a partition, and then installing Qubes with grub installed in MBR.

If you take this approach then you need to add to /etc/grub.d/40_custom in Qubes dom0:

menuentry "Other Linux" {
set root=(hd1,X)
chainloader +1
}
(Change X to reflect the relevant partition where grub is installed.)

Then update the grub config:

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

Like, what the hell is grub even, let alone how to add that string in /etc/grub.d/40_custom in Qubes dom0 in ummm…Qubes dom0??

Stupidest “guide” tbh.

And 2), I want a type of set up where I am able to see a menu with the 3 OSs whenever I turn on my computer, and then i would select the one i want to boot into for that session. How can i achieve this?

Currently, I have a dual boot situation of Windows and Ubuntu. But not like how i described above. I have to select which OS i want from BIOS/UEFI. I assume the above guide is for this type of setup.

I understand the risk of running a multibooot with Qubes.

Appreciate any help!

2

I’ve had the best experience using multiboot with 3+ OSes when using rEFInd.

3

You could figure out what grub is and add menu entries for the systems you want

The guide describes a setup where you already have Qubes installed and want to add other systems as options in Qubes’ grub menu.

I assume it is done so because Qubes OS boot is relatively complicated (and thus the menuentry script is complicated too). Adding other systems to the grub installed with Qubes OS is “easier” than the other way around.

But even that is not a real problem because you can chain load Qubes OS’ grub from a different grub. Ironically, this is what 40_custom from the guide does to other systems.

It is what Micah is referring to as well, I think. Instead of figuring out how to boot each and every system in a centralized grub configuration, you install your “main” grub in MBR, install “subordinate” grubs (together with their systems) on drive partitions, add a bunch of chainload entries for the “main” grub, and tell your BIOS to load the main grub on boot.

4

If you are looking to “learn Linux”, then go for it and learn it.

If you are looking for a reliable computer that boots when you want / need it to, then rather run Ubuntu and Windows inside of Qubes :wink: and don’t setup dual boot. Dual boot will also mean that if Windows or Ubuntu get hacked, they will have access to the /boot partition of Qubes, which is BAD, VERY BAD.

So my advice would be: install Qubes, and use windows in there. If you want to use Windows for gaming, then it might be best to switch hard drives (or use a dedicated box for gaming) - or use geforce now inside of a Qubes VM, which works really well. If you have a GPU you can even use that in Qubes too (depends on the GPU a bit, its a bit hacky sometimes), if its for gaming you’ll need a second monitor, if its for LLMs you can do that quite well.

But like long story short - you are most likely on the wrong path, and if you are not sure about what grub and dom0 is.. I wouldn’t recommend to start your Linux journey there, bcs if you break it (grub especially) then nothing boots and you’ll be very very frustrated with it all.

Do a proper backup to an external medium and switch to Qubes completely. Trust me, you’ll love it :wink:

Currently, I have a dual boot situation of Windows and Ubuntu. But not like how i described above. I have to select which OS i want from BIOS/UEFI. I assume the above guide is for this type of setup.

I missed this before, this suggests you have multiple disks. This is good, stick with this. If you want Qubes for security disconnect the windows/ubuntu disk when using Qubes, and the other way around. If you don’t care and just find Qubes interesting for now you can skip this, but stay with BIOS selecting which disk to boot from. If you mess up grub nothing boots, and then you will miss out on all the less complex very cool stuff you can do with Qubes :wink:

Btw the guide isn’t stupid, its just rather advanced level cause bootloader stuff and what not. You’ll get there, but its not for written for entry level Linux knowledge, bcs the topic just is a bit complex.

Qubes is not really designed to be dual booted for the reasons stated above, so there is no enduser friendly solution for it, bcs its discouraged and nobody really does it.