Every issue of Ubuntu LTS since 8.04, I have made a Full install of Ubuntu to USB flash drive, and recorded each step..

This has been intended to make a guide/check list for users wishing to create Full install bootable flash drives.

Previously the procedure worked for BIOS boot if created in BIOS and for UEFI boot if created in UEFI.

This year for 20.04 the instructions should work for both creating and running the drive booted from either BIOS or UEFI.

The question is:

How to Create a Full Install of Ubuntu to USB device with Step by Step instructions that work in either BIOS or UEFI.

  • My aplogies to post this as an Answer but I cannot add comments (my reputation is nonexistent) This is a question for the OP (possibly a dumb one) C.S.Cameron. When you say "adjust for larger drives". do you mean:' 32 GB ==> all partition sizes times 2 64 GB ==> all partition sizes times 4 etc.? except for "bios_grub" and "boot,esp" I guess PS: Great thread btw, I wish I could add more ups.
    – Caligola
    Apr 3, 2020 at 5:47
  • Thank you: If you build your system with everything you need on a 16GB drive and you clone that to 64GB drives you will have 3/4 of the drive unformatted. Do you want to reserve that space as ext4 for data and future programs or as a FAT32/NTFS data partition that Windows can also use? If Windows is not a factor forget the NTFS partition and use available space for the EXT4 partition. After cloning use GParted to stretch that partition to fill the drive, (except for the last 1MB on the right side). If you want lots of NTFS data space stretch the NTFS partition. Or a little of each. Apr 3, 2020 at 6:28
  • I know Im a pain but don't really know how to do these 2: - Copy the boot and the EFI folders from the Live USB to the boot,esp partition sdx3. - Copy grub.cfg from partition sdx4 /boot/grub/ to partition sx3 /boot/grub/.
    – Caligola
    Apr 3, 2020 at 10:25
  • Open Files, (Nautilus), and right click on the Ubuntu.iso file, select "Open With Archive Mounter", The Ubuntu.iso file will appear on the left, (like a folder), open it and you will see a bunch of folders, Boot and EFI can be copy pasted to sdx3. First open Disks and select your USB, left click Filesystem 3, click the triangle button, click the link lower right. sdx3 will open, paste Boot and EFI. Click Filesystem 4, Click the link, open boot, open grub, copy grub.cfg, open grub on sdx3 and overwrite grub.cfg with the copy from sdx4. Apr 3, 2020 at 11:13
  • I can neither see the ubuntu.iso file in Nautilus nor have any "Archive Mounter" option in the right click dropdown (Open with... doesn't help either). I think I made an "original mistake". As a live usb I am using the iso image downloaded from the official site flashed with UUI (Pendrive linux) from windows, while your instructions call for making it from a working linux environment with SDC, Unetbootin, etc.
    – Caligola
    Apr 4, 2020 at 6:52

1 Answer 1


Follow this link for a step by step guide for Ubuntu 22.04.

Creating a Full Install of Ubuntu 20.04 to USB that works in both BIOS and UEFI

Following is based on a 16GB Target drive, adjust for larger drive. This looks like a long list but, should take less than ten minutes to do the work. K1tty has done an excellent job clarifying many points in this answer, see https://askubuntu.com/a/1332619/43926

  • Create a Live USB or DVD using SDC, UNetbootin, mkusb, dd, etc. (See Note 1 at bottom)
  • Turn off and unplug the computer.
  • Unplug the power cable from the hard drive or unplug the hard drive from the laptop. (See Note 2 at bottom)
  • Plug the computer back in.
  • Insert and boot the Live USB or Live DVD. (Booting BIOS mode preferred).
  • Select Language and Try Ubuntu.
  • Insert the target flash drive.
  • Start GParted.
  • Unmount any mounted partitions.
  • Select Device tab and create a GPT partition table on the Target drive.
  • Create a 3GB NTFS or FAT32 partition on the right side, (optional Linux / Windows data partition, See Note 3 at bottom).
  • Create a 1MB partition on the left side, format as unformatted.
  • Create a 300MB FAT32 partition next to the 1MB partition.
  • Create a 7GB ext partition next to the 300MB partition.
  • In the remaining space create an ext4 partition, (optional for /home partition).
  • Apply All Operations.
  • Flag the 1MB partition as bios_grub.
  • Flag the 300MB partition as boot,esp.

Image of GParted

  • Start Install Ubuntu.
  • Select Language, click "Continue".
  • Select Keyboard layout, click "Continue".
  • Select Wireless network, click "Continue". (optional).
  • Select installation preference and select "Download updates while installing Ubuntu", (optional), and Select "Install third-party software ...", click "Continue". (Optional).
  • If asked about mounted partitions, select Yes, click "Continue".
  • Do not use Advanced feature disk encryption for this install method. (See Note 3 at bottom).
  • At "Installation type" select "Something else", click "Continue".
  • Under Device for boot loader installation select the target drive.
  • Select partition sdx4 and click change, select use as Ext4, select format this partition, and Mount point = "/" then OK.
  • If asked to Write previous changes... click Continue.
  • Select partition sdx5 and click change, select use as Ext4, select format this partition, and Mount point = "/home" then OK. (optional).
  • Click Install now.

Image of  Something else

  • Confirm partitions to be formatted if asked, click continue.

  • Select your location. click "Continue".

  • Insert your name, computer name, username, password and select if you want to log in automatically or require a password. - Click "Continue".

  • Wait until install is complete.

  • Do not reboot or unplug the target USB.

  • Copy the boot and the EFI folders from the Ubuntu ISO file to the boot,esp partition sdx3.

  • If there any problems with permissions, etc, open Nautilus using sudo -H nautilus and try copying again.

  • Copy grub.cfg from partition sdx4 /boot/grub/ to partition sdx3 /boot/grub/ overwriting the grub.cfg file.

  • Re-Install GRUB:

    sudo mount /dev/sdx3 /mnt
    sudo grub-install --boot-directory=/mnt/boot /dev/sdx

  • Turn off computer and plug in the HDD.

  • Replace the computer's cover.

Note 1, Booting ISO Files.

  • If you want the USB to have the ability to boot ISO files using GRUB, create the boot drive using mkusb with the usb-pack-efi option. (this replaces GRUB 2.04 with 2.02).
  • Alternatively you can put rmmod tpm anywhere above the first menuentry in grub.cfg.

Note 2: Hard drive removal.

  • You may omit disabling the hard drive in BIOS boot if after partitioning you choose to install grub to the root of the USB drive you are installing Ubuntu to, (ie sdx not sdx1). Be cautious, many people have overwritten the HDD MBR as default location for boot loader is sda, any items in the internal drive's grub will be added to the USB's grub. You may do an update-grub later. If you leave the HDD plugged in with UEFI install, fstab may use the HDD's UUID for /boot/efi. In this case # or delete the /boot/efi.UUID line in fstab.

Note 3: Apple compatibility.

  • If you own an Apple computer make this partition FAT32.

Note 4: Encryption (optional).

  • +1; Good and detailed description. Have you done thiis when booted in UEFI mode as well as in BIOS mode? Would the same instructions work in both cases? (Maybe you have explained it already, but I did not find such details.)
    – sudodus
    Mar 17, 2020 at 14:04
  • If you cannot disconnect drive, you may have UEFI drive settings to disable it. I just unmount & mount correct ESP during install. Posted work around to manually unmount & mount correct ESP during install #23 & #26 bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1396379
    – oldfred
    Mar 17, 2020 at 14:27
  • 1
    @sudodus : I have been testing for about two weeks now, I have built the drive booted both from BIOS and UEFI and have run the drive from BIOS and UEFI. All work OK for me. I have also built the drive using a mkusb Live drive that was created with the usb-pack-efi option. This booted extra ISO files per Note 1. I would be happy if you gave it a check, it only took me 6 minutes from booting the live drive to typing my name and password. Mar 18, 2020 at 4:44
  • @oldfred : So far, I have not had a problem disconnecting USB, however I am on vacation and only have two computers with UEFI on me. other computers are BIOS only. Mar 20, 2020 at 8:45
  • 2
    @Shateel I have upgraded Full install USB's many times and never had a problem. Feb 7, 2022 at 16:30

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