So I want to install Lubuntu to a 16GB USB Flash Drive and I have a question about the install process: how should I partition the device? I have an Asus X550LB notebook and the specs are: 4GB RAM, I7 4500U and Nvidia 740M GPU. The MOBO uses legacy bios.

  • Welcome to Ask Ubuntu. If it were me, I'd partition the flash-drive as a single partition. Ubuntu 18.04 LTS (including Lubuntu) can use swap partitions or swap files (default on 18.04), so you don't need a separate partition. I would make it use an existing swap partition on a installed hdd (if there is one), as swap on thumb-drives is hard on the device (shortens life with all the writes), or reduce swappiness (even have swap-off if you can), but your intended use will dictate if you need swap. Your intended use will also dictate /home needing to be on it's own partition (but I'd opt no) – guiverc Feb 2 '19 at 10:07
  • @guiverc my intended use is to surf the internet – Davidoff7776 Feb 2 '19 at 10:17

Do you intend to use Lubuntu on this USB flash drive in one computer or in a few computers or in several computers?

  • An installed system is portable between computers, but

  • a persistent live system is more portable.

  • On the other hand, an installed system is more stable and can be updated & upgraded without limits like any installed system (like in an internal drive),

  • while a persistent live system can install and upgrade application programs, but not the linux kernel and not device drivers, that are started directly by the kernel.

See this link and links from it for more details,

How do I install Ubuntu to a USB key? (without using Startup Disk Creator)

The main general advice is to disconnect or turn off the internal drive before you start installing into the USB flash drive. This helps to

  • avoid mistakes (overwriting the internal drive) and also
  • write the bootloader to the USB flash drive (important particularly if you install in UEFI mode.)
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  • 1
    I want to use the USB only on my laptop because I have to take the internal HDD out of it – Davidoff7776 Feb 3 '19 at 16:14
  • In this case you need not worry about portability, and not worry about any problem, that the bootloader will go to the internal drive :-) So just go ahead with 2 USB drives. Make the slower one into a USB live drive (by cloning from the iso file) and then boot from the USB live drive and use Ubuntu's installer to install into the faster USB drive. If a USB pendrive you may want to modify as suggested in the link (in my answer) in order to reduce wear. – sudodus Feb 3 '19 at 16:29

Full Install to USB

Full installs are more stable and secure than persistent installs, but not as quick to make. They are better at utilizing disk space as no fixed size casper-rw file or partition is required. They are not very good for use of installing Ubuntu.

Following is a step by step how to install 18.04 on a 16GB flash drive with options for separate Home partition and Windows compatible data partition:

  • Create a live USB or DVD using SDC, UNetbootin, mkusb, etc.
  • Turn off and unplug the computer. (See note at bottom)
  • Unplug the power cable from the hard drive or unplug the hard drive from the laptop.
  • Plug the computer back in.
  • Insert the flash drive.
  • Insert the Live USB or Live DVD.
  • Start the computer, the USB/DVD should boot.
  • Select language.
  • Select install Ubuntu.
  • Select Keyboard layout
  • Select "Continue".
  • Select installation type and "Download updates while installing Ubuntu" and Select "Install third-party software ...", (optional).
  • Select "Continue".
  • At "Installation type" select "Something else". (Full disk encryption is now working with flash drives).
  • Select "Continue".
  • Confirm target device is correct.
  • Select "New Partition Table".
  • Click Continue on the drop down.

(Optional FAT32 data partition for use on Windows machine)

  • Click "Free space" and "+".
  • Make "Size..." about 2000 MB.
  • Select "Primary".
  • Location = "Beginning of this space".
  • "Use as:" = "FAT32 file system".
  • "Mount point" = "/windows".
  • Select "OK"

(Non Optional Root Partition)

  • Click "free space" and then "+".
  • Select "Primary", "Size ..." = 4500 to 6000 MB, "Beginning of this space", Ext4, and Mount point = "/" then OK.

(Optional home partition)

  • Click "free space" and then "+".
  • Select "Primary", "New partition size ..." = 1000 to 6000 MB, Beginning of this space, Ext2, and Mount point = "/home" then OK.

(Optional swap space, allows hibernation)

  • Click "free space" and then "+".
  • Select "Primary", "New partition size ..." = remaining space, (1000 to 2000 megabytes, or same size as RAM), Beginning of this space and "Use as" = "swap area" then OK.


  • Confirm "Device for boot loader installation" points to the root of the USB drive. Default should be OK if HDD was unplugged.
  • Click "Install Now".

  • Select your location.

  • Select "Continue".
  • Insert your name, computer name, username, password and select if you want to log in automatically or require a password.cscameron
  • Select "Continue".
  • Wait until install is complete.
  • Turn off computer and plug in the HDD.
  • Replace the computer's cover.

Note: You may omit disabling the hard drive if after partitioning you choose to install grub to the root of the USB drive you are installing Ubuntu to, (ie sdb not sdb1). 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.

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