Create a separate efi partition on a dualboot

Hello folks :wink:

I have seen this a lot of times and this causes some problems. It is nice to have a shared efi partitions, but sometimes problems occur. I am not a specialist, but rather a “learning by doing” specialist like many others.

  1. Manjaro has a customized grub bootloader is not compatible with the debian/ubuntu one as far as i know. This causes problems for newbes, when they update grub through debian/ubuntu and maybe other Distros.
  2. Windows like to reformat or overwrite the efi partition at updates. At least on my experience. Therefore, to avoid a broken bootloader, it is nessecary to have separate efi partition.

Grub can find other efi partitions and most UEFI’s can handle more than one efi partition. So to close these issues, i would suggest to make calamares creating its own efi partition like windows does.

The default installation should include a new efi partition and it should be avoided to use the efi partition created by windows or other Distro’s.

Any comments?

It sounds good in theory, but depending on your motherboard can effect whether or not it will scan for all FAT partitions when searching for EFI boot files.

For example, mine will not find nor display any entries for boot files that live on any other FAT partition other than the one designated as my EFI System Partition (esp).

With two drives, however, I can have two different esp’s, because each drive gets its own designated esp, and hence my system will present to me EFI boot entries from both partitions (and I can choose which one is the “default” to boot into.)

Ever since installing Windows 10, I’ve had Windows and Linux sharing the same esp, and Windows 10 has never reformatted my esp, nor deleted anything Linux-related.

Are you referring to when you reinstall Windows? That might be a different story.

Ok i made some research. According to the UEFI specification there is no limit of esp partitions. Therefore I guess it is a wrong configuration in your case. Maybe you have not flagged all esp partitions as boot?

It was really an update. Windows was able to boot, but manjaro was broken afterwards (the grub efi file was just not there). No idea why this happens. I usually only use linux, one day i booted into windows and made a big update, afterwards Manjaro was not bootable and the efi file, even the folder was not there anymore.

Running the command,

sudo blkid -p -o value -s PART_ENTRY_TYPE /dev/nvme0n1p2

Yields the following,

c12a7328-f81f-11d2-ba4b-00a0c93ec93b

(nvme0n1p2 is the second partition of my NVMe drive.)

If you search Google for the exact unique GUID c12a7328-f81f-11d2-ba4b-00a0c93ec93b, you’ll see it’s reserved for the EFI System Partition. Each GPT table (per drive) can only have one partition with that particular GUID. I cannot have more than one GPT partition with the GUID of c12a7328-f81f-11d2-ba4b-00a0c93ec93b, per drive.

So perhaps some motherboards/UEFIs only scan that partition for EFI boot files, while others just scan every available FAT partition? Mine falls on the former.

Windows gives me the heebie jeebies when it meddles in low-level stuff like that. :grimacing: I guess I’ve been lucky so far.

Ok I checked that:

$ sudo blkid -p -o full -s PART_ENTRY_TYPE /dev/sda1 /dev/sda3                                           
/dev/sda1: PART_ENTRY_TYPE="c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
/dev/sda3: PART_ENTRY_TYPE="c12a7328-f81f-11d2-ba4b-00a0c93ec93b"

So this is wrong then:

Both work and i had even more created for testing purpose. 6 Distros + Windows at the same time on the same drive. No issue with having 7 esp partitions.

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Then I stand corrected! This gives me a bunch of ideas going forwards myself. Thanks for letting me know. :slight_smile:

Now I’m curious, and to be clear, Windows never touched your other EFI system partitions, only the one that it used itself during its initial install? Or did it meddle with the other ESP’s?

This is one for the Manjaro team, and my guess is they might not be too comfortable with implementing this as a “default” behavior. “If it ain’t broke, don’t fix it” sort of thing.

But after reading what you just shared, I would probably use it myself, perhaps. Though I’ve never bumped into a situation where I lost my boot files from a Windows update, and for some users it might be considered a small waste of space to create an ESP per OS, when they can use their already existing one.

I am not 100% sure, but windows “mounts” the partitions also by some kind of UUID. Therefore windows only uses its own esp partition, i mean the one windows created itself and never touches the other esp partitions.

You can also install a distro first and then install windows. You just have to install it in advanced mode and assign the space. There windows will create a new efi partition.

Edit: Confirmed. Windows uses GUIDs:

grafik

Maybe at least it would be good to have a checkmate box so that it creates separate efi partition. Which would be fully optional.

Try it :wink: It makes my life more comfortable.

Well, if you use one esp partition per OS, then it don’t have to be 500MB. 100MB max is quite enough.

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So after seeing my therapist and doing some deep introspection during my daily meditations, I have to say I’m onboard with this idea. But there are a few caveats and suggestions:


I would rename your thread title to remove the word “default”, as it suggests changing the default behavior of the installer.


This is partially true, as it depends on how the user’s PC was partitioned “out-of-the-box”. I don’t know for sure, but what if some PCs ship with a hefty 256MB or 512MB EFI system partition? Would resizing it make Windows complain? I haven’t played around with that before.


I think the idea is great, but not as a “default” behavior. Using the existing EFI system partition has done well for the installer, and so to stray away from this as the default might not be worth the risk of unforeseen issues during/after installation.

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