How to make a bootable USB drive on Ubuntu 16.04

How can I make my pen drive a bootable device? Currently I'm using Ubuntu 16.04 LTS.

Previously I tried on Windows OS using third party software.


Persistent Install vs Full install

Ubuntu can be installed to a USB in different ways. A Live install does not save between sessions. A Persistent install extracts the OS from a compressed file and saves data to an overlay file or partition each session, and a Full install installs the complete OS to the USB just like an install to internal disk.

Comparison between Persistent and Full install USB

Advantages of a persistent install:

  1. You can use the persistent pendrive to install Ubuntu to another computer.

  2. A persistent install takes up less space on the pendrive.

  3. You can reset the pendrive by overwriting the old casper-rw file with a new one.

  4. The install to pendrive takes less time.

  5. Slightly less wear on the drive.

Advantages of a Full install:

  1. You can update and upgrade.

  2. If you have problems or wish to modify, the solution is the same as with an internal install, (You can ask for help in the forums).

  3. No ugly startup / install screen.

  4. Better security, you can use full encryption

  5. You can use proprietary drivers.

  6. Swapfiles and partitions work and Hibernation can be enabled.

  7. Many persistent installs are limited to a 4GB casper-rw and a 4GB home-rw persistence file, to get more persistence requires persistence partitions. Once casper-rw is full, the drive will not boot.

  8. More efficient usage of disk space. Does not require reserved space for persistence.

  9. Faster boot, no automatic disk checking or Try Ubuntu/Install Ubuntu screen.

  10. You can run VBox and use virtual machines.

  11. Generally faster boot than Live or Persistent USB's.

  12. More stable, better for day to day use. I have run Ubuntu off a flash drive for 5 years making only LTS upgrades.

Note that once booted, both methods run at about the same speed. If the computer has lots of RAM Ubuntu should run mainly in RAM and there will not be a big difference between running off internal HDD and USB3 flash drive f.

Full Install Method

A quick and easy method to flash a Full install to USB can be found here: Easy Full Install USB that Boots both BIOS and UEFI

A more traditional methods for creating a Full install USB from scratch can be found here: How to Create a Full Install of Ubuntu 20.04 to USB Device Step by Step


Ubuntu live (live-only) in a USB pendrive

All current Ubuntu versions (for example 20.04.x LTS) and flavours (for example standard Ubuntu, Kubuntu, Lubuntu ... Xubuntu) are distributed with hybrid iso files.

This means that you can easily create a bootable live (live-only) pendrive: clone from the iso file to the pendrive. This is a one-to-one copy where every byte of the iso file is copied directly to the pendrive. Such a drive is good for testing and installing Ubuntu into an internal drive.

The Ubuntu flavours Lubuntu, Ubuntu MATE and Xubuntu have smaller footprints; you can use them in weaker computers (for example less RAM).

  • You can find links to download Ubuntu and the Ubuntu flavours here

  • There are instructions

    • how to create a live drive in Windows (DD-mode in Rufus is cloning)
    • how to create a live drive in Ubuntu
  • More tips and links can be found here

  • and there: Why Doesn't a Bootable USB Boot

Advanced ways to run Ubuntu from a USB pendrive

The answer by C.S.Cameron contains interesting arguments about something more advanced (than a live-only drive), and links to good descriptions of how to create an installed system in a USB pendrive:

  • a persistent live system

  • an installed system (like into an internal drive, but into a USB pendrive)

and he is recommending an installed system. I agree with many of his arguments, but I think that a persistent live system can also be quite useful, and it can be created from standard Ubuntu or an Ubuntu flavour with

  • Rufus in Windows (works with Ubuntu 20.04.x LTS according to this link)
  • mkusb in Ubuntu (mkusb version 12 (mkusb-dus) works with all current Ubuntu versions)