How to Actually Install Ubuntu on USB – It's FOSS

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Brief: This tutorial shows the steps for actually installing Ubuntu Linux on an external US drive with the bootloader installed on the USB. It is NOT live USB set up. This USB will work as portable operating system and can be used on any computer system.
Let me recall a few things.
A live USB is used for testing the distribution. It is also used for installing Linux on computer hard disk. Normally, any changes you made to your live distribution is lost and this limits the usage of the live USB.
Several of It’s FOSS readers requested a tutorial on installing Linux on a USB. Not the regular live USB with persistence but the actual Ubuntu installed on a USB disk.
This means having a portable Ubuntu Linux on a USB that you can plug it in to any computer, use it, save your work on the USB like it was an actual hard disk.
The procedure does not seem very different from installing Ubuntu on actual hard disk. And this is where people make mistakes.
The available tutorials on the internet miss the most crucial part: the bootloader.
The one major problem with this setup is bootloader installation on UEFI systems. A system can only have one active ESP partition at a time and it causes issues.
While installing Linux, even if you choose the USB as the destination for bootloader, the existing ESP partition is still used for placing the EFI file for the new distribution.
This means that the Linux installed on the external USB will be the last one to update and control the bootloader. This may create several problems like:
This fails the entire idea of having a portable Linux USB, right?
Worry not. I’ll share a neat trick for installing Ubuntu or other Linux distributions on a USB without messing up with the bootloader of the host system and the system on the USB.
Before you start following the tutorial, read it entirely and then go about doing it on your system.
The solution or workaround to the bootloader problem is that you do not let the installer know that there is already an ESP partition.
If you have a desktop PC, you may remove the hard disk and that could solve the problem but things will be difficult when it is a laptop. Removing the disk is out of question here.
An easier way out is to remove the ESP flag from the ESP partition before installing Linux on the USB and put it back after installation. This way, you fool the Ubuntu installer into thinking that there is no existing ESP partition and it will create and use a new ESP partition on the USB. The original ESP partition on the hard disk is untouched.
Clever trick, I know. Let me clear a few more doubts and add some suggestions:
About the slower experience with Linux on USB, if your system has a thunderbolt port, I advise getting a thunderbolt SSD. I have a SanDisk SSD and when I used installed Linux on it, the experience was very smooth, almost like the SSD on the system.
Now that you know what you need, let me lay out the parts of this tutorial:
I am not going in details for this part. You are probably aware of the steps anyway. I am going to briefly mention the steps here. If needed, you can read this tutorial on creating live Ubuntu USB.
On your computer, go to Ubuntu’s website and download a current Ubuntu release of your choice.
There are several tools available for writing the ISO image to the USB. You may use Etcher which is available for Linux, Windows and macOS.
Download Etcher. Plug in your smaller capacity USB. Run Etcher and browse to the downloaded ISO and USB and hit the flash button. It’s really simple.
When you have created the live USB, it’s time to use it to install Ubuntu on the other USB.
Alright! So you have a live Ubuntu USB and an empty USB where you’ll be installing Ubuntu. Plug both of them to a computer. You have to boot from this live USB now and for that you’ll have to access the boot settings.
Plug in both USBs to your system and restart it. When the system is booting and it shows the manufacturer’s logo, press F10/F12 keys repeatedly. Different manufacturers set different keys for accessing the BIOS settings.
Note: Some systems won’t allow booting from live USB if secure boot is on. If that’s the case, disable secure boot first.
On my Dell system, the boot settings showed this screen. I have Debian installed on this system.
When you are in the live session, go with “Try Ubuntu” option:
Press the Windows key and type Gparted. This will open the Gparted partition manager which is (usually) already present on the Ubuntu ISO.
If it is not found, connect to the internet, open a terminal, run sudo apt update and then install gparted on Ubuntu.
In Gparted, make sure that you have selected the system’s disk. Look for the partition of around 100-500 MB in size and flagged as ESP. Right click on this partition and select ‘Manage Flags’:
It should show esp and boot flags. If there are more flags set, take a screenshot so that you can revert to the same set of flags after the installation is complete.
Deselecting the flags usually adds a msftdata flag and you can leave it like that. Changes take into effect immediately.
Great! Now your live system does not see the ESP partition and thus the existing boot settings of the computer. Now is the time to start installing Ubuntu on the other USB.
Make sure that you have plugged in the other, bigger capacity USB as well. Double click on the install Ubuntu icon on the desktop.
It will start the installation. You can go through the first few steps of choosing keyboard layout and language.
Remember, I told you in the beginning that it takes quite a long time in installing Ubuntu on a USB? For this reason, I suggest going for the minimal install here which comes with a browser and essential utilities but won’t include office software, media players etc. You can install them later.
Using Minimal Installation means copying less files on the USB and this will reduce the installation time.
On the next screen, select Something Else:
On the ‘Installation type’ screen, you can see all the hard disk and the USB disks listed on the main interface. You can see that the hard disk doesn’t show an ESP partition because the flags have been removed.
What you should make sure here is that you have selected the correct USB (the bigger one) for “Device for bootloader installation”. I am using my external thunderbolt SSD here which is of 500 GB capacity (bigger than the hard disk of the laptop):
Now, select the bigger USB and delete any existing partition to make free space by clicking the – button.
Next, select the free space you just created and click the + sign to make partition on it.
Make the first partition as ESP for the bootloader.
Select the remaining free space and create root with Ext4 filesystem. You may also create root, swap and home but I suggest keeping everything under root including swap (thanks to swapfile).
When you have the partitions ready, double check that external USB is chosen for the bootloader install.
Things are looking good. Hit the install button and go through the usual timezone settings.
You’ll be asked to create user and password.
After this, it is all a matter of waiting. If you have ever installed Ubuntu, you’ll surely feel that this installation is slower than usual.
When the installation finishes, DO NOT RESTART right away. You have to reset ESP partition back in its original state.
Start Gparted once again. Select the hard disk of your system and right click on its ESP partition which is now labelled as msftdata. Select esp flag and it should also select boot flag automatically.
Congratulations! You have successfully installed actual Ubuntu on a flash drive. You can now turn off the live Ubuntu system.
That’s bad nut not too bad. Since your actual system does not have an ESP partition it won’t boot without the external USB you just created.
But no need to worry. You still have the live Ubuntu USB, right? Boot from it again. Start Gparted and enable the correct flag on the ESP partition of the disk.
The USB you just created can be used on any computer as long as it allows to boot from the USB. In other words, secure boot should be disabled.
I verified my Ubuntu USB of two systems, one on which I created it and another one which was not used in this process. It worked on both.
The process is similar to how you booted from the live USB. You turn on the system, when the system manufacturer’s logo is visible, press F2/F10/F12 keys to access the boot settings and select Ubuntu or USB to boot from. It may be displayed with either of the two names (or more perhaps).
When you boot from the Ubuntu USB, you’ll see the familiar Grub screen and you can select Ubuntu to use it:
Did you notice something in the above Grub screen? I used a system which had Debian installed for creating this Ubuntu USB. While installing, the new ESP partition on the USB also takes note of the Debian system as you can see in the Grub screen.
If I use this USB on a different system and try to boot into Debian, it will throw an error. Obviously, because there is no Debian system on the new system. If I use the USB on the same Debian system which was used for the Ubuntu installation on the USB, it will work.
The extra entry in the Grub should not bother you unless you have obsessive compulsive disorder. If that’s the case, boot into this USB, install Grub Customizer and delete these additional entries. That’s up to you.
Another thing to note is that when you boot from the Ubuntu USB on a different systems It shows a blue screen with a few options. Just go with boot anyway.
There is one last thing remaining, and that is to claim your USB drives back.
Here’s the thing you have used two USBs: one for live Ubuntu and one for actual Ubuntu install.
If you want to use either of the USB later for normal data transfer, you’ll have a difficult time formatting them. When you create a live USB, it leaves the USB in a weird state and often operating systems cannot format it directly.
Gparted comes to rescue once again. It is available for Linux, Windows and macOS. Download and install it and use it to format the USB by deleting all the partitions on it and the creating a new partition in NTFS or FAT32 format.
The neat trick of hiding the actual ESP partition from the Ubuntu installer is the key idea here. This is a better solution than removing the hard disk or having a messed up boot.
I hope you like this trick and find this detailed tutorial helpful.
If you still have questions about installing Linux on USB, please ask them in the comment section and I’ll try to answer them.
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Filed Under: Tutorial
Creator of It’s FOSS. An ardent Linux user & open source promoter. Huge fan of classic detective mysteries ranging from Agatha Christie and Sherlock Holmes to Detective Columbo & Ellery Queen. Also a movie buff with a soft corner for film noir.
So if I want to install other linux distr also using this method e.g linux mint?
It should work for other distros as well.
Thanks a lot for this great tutorial.
The images were not loading on my Safari, but I still managed to go through.
I tried to load the page on Chrome afterward, and all the images could load….
How long did it take you to install the basics on the 500GB HD?
I’m installing on a 200T SSD and it’s really slow.
It took me 20 minutes I think on the external SSD.
Sorry.. is 2T
mine has been over 12 hours and says it is creating root partition
I run into the same issue and I tried many solutions nothing worked form until I changed the USB
Hello, I have a question regarding disabling the ESP flag so the installer does not know there is already an ESP partition. I followed the instructions installing Neon KDE instead of Ubuntu. Everything worked fine, no errors. Looking at the UEFI settings I see an entry for Neon along with other operating system installed to the internal hard disk. I was not expecting to see Neon listed as the ESP flag was disable before installation.
I have checked the ESP directory using diskpart and there is no entry for Neon, but UEFI shows an Neon entry. I am confused could you explain what is happening here.
Hey Stewart,
If you remove the external USB with KDE Neon installed, do you still see the Neon entry in UEFI?
This instruction is excellent to understand and conduct the installation. Thank you for the perfect post.
I am glad you liked the instructions 🙂
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