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I have Ubuntu 20.04 installed on my machine. My current HDD fas following partition status, after Once dual booted windows 10 (I uninstalled it).

enter image description here

I found the UX of POP OS very intimidating, and being a ubuntu user it won't be a huge change. So I have decided to dual boot pop os 20.10 with existing ubuntu 20.04.

Problem:

As I went ahead with live booting pop for installation, it asked for a new ESP along with it's new root partition. It seemed the current esp (100 mib is not enough) and a 512 mib is needed.

What I did: I installed pop os creating a new esp for it. But after that I could not find ubuntu on pop's Systemd-boot. Now there seemed some work around. But I don't wanna have two efi partitions on my disk. Only one is allowed. I booted to ubuntu from bios menu. And deleted pop partition.

My query: How do I install pop os with one esp partition (feel to create a new one) dual booted with existing ubuntu?

Can I merge current esp with left-side unallocated 500mb (old windows recovery disk) to make it larger.

I am not sure whether:

  1. Creating a new ESP partition (1 GB)
  2. Mmoving current esp /boot/efi data to the new esp
  3. Deleting current esp partition
  4. Installing pop on new esp

would work.

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  • 1
    If you delete & recreate a new larger ESP, you will have to totally reinstall grub. Both UUID & GUID will change. GUID aka partUUID is used by UEFI to know which partition is ESP. And UUID is used by fstab entry to know where to reinstall grub files. Using gparted on live installer, you may be able to move left & expand right without it changing UUID & GUID. But I would have Ubuntu live installer handy, just in case. Also if you have to reinstall check that Ubuntu entry uses new GUID. Compare sudo efibootmgr -v and partUUID: lsblk -o +PARTUUID /dev/sda
    – oldfred
    Jan 27, 2021 at 19:49
  • Seem's like expanding ESP is too hard, just read this answer
    – Sayan Dey
    Jan 27, 2021 at 20:13
  • I had to uninstall manjaro :( for it's not booting problem once I successfully resolved it's booting grub menu issue. I want to go on with two esps and f12 hitting to reach BIOS menu and choose from there. Thanks for your clarification @oldfred
    – Sayan Dey
    Jan 27, 2021 at 20:16

2 Answers 2

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I'm triple-booting Ubuntu, Debian and Windows 10. The ESP (EFI) partition is 512MB large for me, but all these operating systems use only 39MB, so I don't think it's a problem of lack of storage space.

  1. Make sure you're booted using UEFI (not legacy)

    ls /sys/firmware/efi
    

    If you get a list of files, you're booted using UEFI. Instead, if you get a "No such file or directory" error, you're booted using legacy.

  2. Make sure you selected the EFI partition before the installation. The installer should do this automatically, but still check if it's tagged as "EFI System Partition".

  3. Edit: I forgot to add this additional step. It's not necessary as your operating systems are already installed using UEFI.

    Check if your hard drive is formatted as GPT. You can use the GNOME disk utility to check: GNOME disks partition table check

How to grow the EFI partition?

If the steps above don't help, you can still try to grow the EFI partition.

  1. Open GParted and right click on the ESP.
  2. Select "Move partition" and drag it to the beginning of your partition table. Confirm the change and wait for it to complete.
  3. Your EFI partition is now in the beginning of your partition table and you can easily grow it by right-clicking the partition and selecting "Resize".
  4. Apply the changes and repeat the installation.
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  • I am sorry for the late reply. Yes the installation is UEFI. And yes the storage is an issue. Pop os on the new efi is taking 100 mb currently.
    – Sayan Dey
    Jan 29, 2021 at 5:03
  • Also I don't want to expand the partitions as I see it's a hard and risky thing
    – Sayan Dey
    Jan 29, 2021 at 5:05
  • Thanks for your reply, now I am more confident about triple boot after listening from you. :)
    – Sayan Dey
    Jan 29, 2021 at 5:51
  • @SayanDey I think it should be safe to move and resize the EFI partition. I've done moving and resizing many times and I haven't experienced any problems. If you don't want to move anything, you can try to create an image of the EFI partition. Then delete the partition, and write the old image at the beginning of your hard disk.
    – adazem009
    Jan 29, 2021 at 7:19
  • Oh okay, I will give it a try then, Will create an image of it and move it then.
    – Sayan Dey
    Jan 29, 2021 at 7:53
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Caution: Not a solution rather a workaround with explanation

I digged a bit deep myself and found something working and a sane explanation. I find out this for uefi based systems.

You have basically two boot loaders one for detecting the os partions (from bios) and the other one for loading os (grub bootloader or systemd bootloader or equivalent). The grub part stays inside /boot and is configurable from os-side.

So in my case, I can simply keep two esp partitions on the same drive. One grub will override (possibly the one which installed it's grub most recently). The only thing is I will be defaulted to one grub (as in my case pop os and ubuntu are not sharing their grub).

So, I set grub timeout to 120 for both pop and ubuntu. I press f12 while booting and I am taken to the bios menu which enlists both legacy and uefi bootables (first bootloader). There I can find all esps and corresponding os installations and select to boot into one.

Limitaion:

  1. This is not a soultion of single esp.
  2. You don't utilize grub in this case.

Good side:

  1. Well the things are modular in this case.
  2. Installing and uninstalling os is super cool with deleting the corresponding esp and
    root partition.

Update:

enter image description here And doing a sudo grub-install /dev/sda and sudo update-grub from ubuntu, appended POP OS into it's grub entry. So, now I use ubuntu grub menu and boot select Pop or Ubuntu.

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