Do I need extra efi (fat32) partition for dual boot?

I want to dual boot win11 and EndeavourOS on my laptop, which has one 1TB ssd.
The laptop is already installed with win11, I plan to partition out about 500G and install EndeavourOS,
but when I install new OS to the new empty partition, do I need to create a new efi partion, which mount to /boot/efi, or I should use the efi partition of win11?

If I need to use the win11 efi partition, how and what size should I resize it?

No, not necessarily.

You could use the same. Just make sure to NOT format it when you install EnOS

Normally you don’t have to resize it. The installer should just detect it and install EnOS’ bootloader in a separate directory side by side that of Windows.

However if you want to effectively isolate the ESP partitions for each system, then you could create a 300 MiB FAT32 partition. You chose the manual install in the installer and mount this partition at /boot/efi and flag it as boot.

Further reading:

Normal installation put windblows on first then Linux is the proper way of doing it.

If you do it the other way windblows will over write the linux boot.



Only if MBR/Legacy install.
Not so for UEFI mode installation.

I think it can as i have done it myself. Even so couldn’t you just arch-chroot and reinstall grub?

In my experience with installing Win 10 where already a Linux system was present on the disk installed in UEFI, Windows installer just put its bootmgr in a separate directory on the same ESP.

I have done it a couple of times and my Linux boot never was overwritten.

The MBR/Legacy is another story though.

Just to pile on: Install Win 11 first, then use the disk management gui to shrink the Windows partition. No need to resize the EFI partition. Use Calamares to install EOS to the unallocated space. EOS will overwrite the EFI partition. When EOS boots it will offer you a choice of Windows or EOS–maybe. Sometimes OS-Prober doesn’t work right on EOS. There’s a procedure described in several places on this forum on how to enable OS-Prober for dual-boot. Just do a search for it. If it still doesn’t work, install rEFInd. That’s what I’m using to dual-boot Fedora and EOS on my ancient Thinkpad.

Well to be fair I’m not saying it does. I have just had it happen to me but it could have been my incompetence at the time. :rofl:

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Well, the case at hand is anyways about installing EnOS where already there is a Windows system installed:

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Since dual booting is against my religious beliefs, I will just welcome @yuanhao aboard the good ship :enos: As you can see we are a friendly bunch :upside_down_face:

When it comes to operating systems, I am an atheist :wink: :sweat_smile:

I triple boot. All EOS! Actually there are 4 as I3 and Xfce are installed together. :scream_cat:

Don’t you mean agnostic? :wink: :sweat_smile:

No, I believe in none of them!
But I have to use them on a daily basis.

Nice turn on words. I would remember for future use, but that’s not going to happen since I deleted the windblows partition over 2 years ago. We are a :no_entry_sign: :window: household.

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But Rick, you are wierd. That doesn’t count :rofl:

FWIW in my experience with UEFI troubleshooting, WinOS does not overwrite files/folders that belong to another (Linux) OS, but it will definitely change UEFI Boot Order, which results in the same problem.

IIRC a few years back, in another support forum, there were at least a couple of reports about folders were vanished, but this is probably not because of WinOS, but from the UEFI firmware possibly being reset. I don’t remember exactly the outcome of those investigations, but I am sure that, even if WinOS really deleted folders, they must have corrected this behavior, as it is a bug.

My answer to this topic would be “You don’t necessarily need an extra ESP partition, but it is not a bad idea to have one and always be prepared to chroot and change UEFI boot order”, unless you have confirmed experience that your UEFI settings include a feature to successfully change OS (not disk) boot order from UEFI GUI.

Always remember that

  • not every UEFI implementation is the same or with the same features/capabilities.
  • if you let WinOS perform its updates, it will most probably change UEFI boot order and set WinOS as first (if not always, with major updates it is always true). All OSes use the same attitude, make themselves first to boot.



Changing the bootorder and overwriting boot files/folders won’t result in exactly the same problem.

While the former will leave your Linux in a bootable state and oftentimes can be remedied by going into the firmware settings and changing the boot priority, the latter would make it unbootable and it needs chrooting and the rest of the story to make it bootable again.

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I thought I had said the same thing… :thinking:
I did not define the problem :slightly_smiling_face: , which is a newly installed system that fails to boot, at least this is the experience that an inexperienced user gets. :person_shrugging: A chroot is the most probable thing they have to do.

There is no disagreement in the essence of the status. :laughing: :+1:

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That’s probably why it wasn’t clear to me which problem

referred to.

At any rates, it’s good to know that there are solutions to bootloader-related unbootable systems whatever might have caused it

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