I was wondering if I could have 2 partitions on a USB-drive that would allow me to boot on my key as a regular USB-installation-disk (partition1), and another partition for regular storage under Windows/Ubuntu (partition2). I would like to have a disk with :

/dev/sdb (16GB)
 - sdb1 : ext4/fat32, LiveUSB (2GB)
 - sdb2 : fat32, storage (14GB)

Could that key be booted AND used as a regular USB drive ?

PS: that is because I'm sick of installing/uninstalling Ubuntu on my USB drive everytime I need to rescue a PC, and I'm not willing to buy a USB-drive only for Ubuntu-installation-disk.

  • 2
    Something similar is very easy to do with Ubuntu 20.04 LTS. mkusb-plug can do it autmatically for you with or without persistence.
    – sudodus
    Jul 2, 2020 at 13:01
  • @sudodus thank you! It really did the trick for me.
    – Sharpey
    Jan 16, 2021 at 15:28

7 Answers 7


Yes, you can partition a USB flash drive to boot into a Ubuntu Live Session and use it as a regular USB drive (accessable to windows) on separate partitions. I was able to do this with a 32GB PNY USB 2.0 flash drive on a Sony Vaio T Series Ultrabook laptop with UEFI and Windows 8.0 installed. I also tested this from Ubuntu server 12.04 on my 16TB RAID5 i7-290 server.

I partitioned the USB flash drive using GParted in this configuration:

32GB USB Flash Drive GParted

sdh1 is the "Storage" partition that's accessible from Windows. sdh2 is the Ubuntu desktop 12.04 boot-able partition. These were my steps:

 1. Created a new 10 GB, ntfs, logical partition, with 25 MB Free space preceding 
and 0 MB following, labeled Storage (must be first on the drive) 2. Created a new 5 GB, fat32, logical partition, with 0 MB preceding and following 3. Set a boot flag for the second partition 4. (Created the other partitions which are not needed) 5. Booted to a Ubuntu Live Session loaded on a DVD and selected Try Ubuntu
without installing from the GRUB menu 6. Opened Startup Disk Creator with the USB flash drive pluged-in 7. The Ubuntu-Desktop 12.04 Image and pny USB 2.0 flash drive (/dev/sdh2) 5.0 GB
partition were already selected, moved the How much slide to store documents
and settings in reserved extra space and selected Make Startup Disk

Without selecting the boot flag, the Startup Disk Creator would only recognize the entire flash drive as /dev/sdh, instead of the desired second partition /dev/sdh2.

Without putting the Windows partition first, the Removable Media Bit...

"The removable media device setting is a flag contained within the SCSI Inquiry Data 
response to the SCSI Inquiry command. Bit 7 of byte 1 (indexed from 0) is the
Removable Media Bit (RMB). An RMB set to zero indicates that the device is not a
removable media device. An RMB of one indicates that the device is a removable
media device. Drivers obtain this information by using the StorageDeviceProperty

...would mean only 1 partition shows up in Windows:

"Q. What is a superfloppy?

Removable media without either GPT or MBR formatting is considered a "superfloppy." 
The entire media is treated as a single partition.
The media manufacturer performs any MBR partitioning of removable media. If the
media does have an MBR, only one partition is supported. There is little
user-discernible difference between MBR-partitioned media and superfloppies.
Examples of removable media include floppy disk drives, JAZ disk cartridges,
magneto-optical media, DVD-ROM, and CD-ROM. Hard disk drives on external buses
such as SCSI or IEEE 1394 are not considered removable."

Here are some tools that flip the RMB (which is unnecessary in this case):
Laxar's USB Format Tool

These are software approaches (again unnecessary in this case):
Create a dummy.sys Driver
Use the Hitachi Microdrive Filterdriver

TSJNachos117 Live USB on a 2-partition usb-drive

  • Thanks, I'll try that. I know I could use a folder inside the same partition, but that is NOT graceful. I want a nice thing, it's in my everyday life and I want some class :) // Not to brag but I also know how to use partition tools; what made me ask was if I could or not boot with a partitionned USB-drive.
    – MrVaykadji
    Feb 20, 2014 at 0:14
  • It does; I just verified to be sure. I like your idea though and am expanding upon it to create 3 partitions: Ubuntu12.04 (bootable), Hirens (bootable), and Storage. I'd like to be classy like that too ;) Feb 20, 2014 at 1:13
  • 6
    Is there a reason for the 25 MB preceding the partitions? Why 25? Does the size differ based on the total space of the flash drive?
    – stevendesu
    Oct 27, 2015 at 20:39
  • 1
    I've just done this for Ubuntu 16.04 and I found unetbootin was the simplest tool to create the boot disk. It picked up that boot flag as you suggested. The Startup Disk Creator kept wanting to wipe the whole disk. Sep 9, 2016 at 21:26
  • 4
    This post is obsolete SDC has not had a persistence pointer since 14.04. Aug 11, 2018 at 17:54

I found an alternative way which is more straightforward. There are 2 important pieces of information one needs to understand about why this works. The first is about the boot process and how the initial power on self test (executed by the BIOS) looks for a boot record on the first boot sector of the devices attached. This is a small file which basically passes the boot execution process onto the boot loader/manager such as GRUB2 on newer Linux installs. For more information on this, read this very informative post.

The 2nd piece of information is to understand that the ISO downloads for Linux OSes are designed to be installed on a disk (CD/DVD/USB) and not for a partition. These ISOs need to be modified using a small tool which can be found on the syslinux-utils package, called isohybrid. The ISO modification for installation on a partition is done with the --partok flag. I found this information from this post which describes the exact same issue. I am not sure how the --partok magic works, I searched for some explanation but could not find any.

In summary, here is what I did to get my live PureOS install to boot from a usb partition,

  1. Partitioned my USB using GNOME disk, I initially formatted the disk using MBR/DOS. I created a 4GB partition (FAT32) followed by a an ext4 Linux partition in the remaining space for my backups.

  2. Next I modified the ISO file I downloaded to make it bootable from the partition. To do this I had to install the syslinux-utils from the repositories, in which the isohybrid tool resides:

    sudo apt-get install syslinux-utils

    I then modified the ISO file with:

    isohybrid --partok pureos.ISO
  3. I used dd to copy this ISO to the above partition. You can get the partition device from the GNOME disk details.

    dd if=pureos.ISO of=/dev/sdb1 bs=1M
  4. From GNOME disk I edited the partition and checked the bootable option, which installs the required book record.

I was now able to boot from the USB key into the live CD and use it as a recovery solution while storing my system backups on the other partition.

  • I tried a year ago to get this to work and failed. Obviously I didn't find this post back then. It works! I wish there was more documentation - I get a warning about not all BIOSes being able to boot my stick, which is indeed the case. But that's still way farther along than I was before.
    – Matthew
    Feb 19, 2019 at 2:34
  • 2
    Works even with more than one other partition (ext4 including luks encryption).
    – David
    Dec 11, 2019 at 16:50

This should be easy to do. However, be warned in advance that Windows will only be able to see the first partition (/dev/sdb1), the second partition will be invisible (I don't know why). Therefore, I would recommend the general-purpose storage partition be the first one, and the LiveUSB partition be the second one.

If after doing this, you can't get the key to boot, you should be able to set the Boot flag using GParted.

Please note: although I've successfully done this before, I've never tested doing something like this on a UEFI-based system, let alone something that uses Secure Boot.

  • I'm afraid I'll have to argue that point. I, myself have a flash drive which I use both as a LiveUSB version of Ubuntu, and for general storage. My first partition is an NTFS partition, which works perfectly on both XP and 7. My second partition is a FAT32 partition, which contains a live version of Ubuntu. I can't even see this partition from Windows, even from the disk manager (diskmgmt.msc). However, i can boot from it, and read from/write to it from Ubuntu. See the 4th paragraphHERE. Feb 23, 2014 at 5:28
  • Apologies for the down-vote. After reading your comment I realized my test Ubuntu Live boot partition was not first. If you make a small edit I will give a well deserved up-vote. Feb 26, 2014 at 4:38
  • 1
    Nowadays Windows 10 allows access to multiple "Windows FS type" partitions. Fat32, NTFS, UDF. Aug 11, 2018 at 18:14
  • 1
    @conman253 small edit has been done...
    – Zanna
    Jul 2, 2020 at 12:35

The simple answer is yes, but you can go simpler!

make sure you an ISO of the Linux flavour you want on the drive and UNetbootin, available from here: http://unetbootin.sourceforge.net/

Make sure you select Hard Disk install from the drop down and to copy all your data from the drive before starting. You should be able to use the rest of the space for your other purposes!

  • That's not really what I want to do, the reason I want to separate partitions is to have a clean storage space, without all the folders from the ubuntu installation disk. Just having them hidden wouldn't work since I use the USB-drive on both Windows and Ubuntu.
    – MrVaykadji
    Feb 19, 2014 at 20:19
  • Also, Unetbootin will only allow me to boot the live in English, and I want to use my native language.
    – MrVaykadji
    Feb 19, 2014 at 20:20
  • Once unetbootin is installed, you can use a partition manager to shrink the partition and add one for your own files after it (gparted would do it perfectly) As for the language change, you can edit the bootloader to to add kernel parameters, see <help.ubuntu.com/lts/installation-guide/powerpc/boot-parms.html> in regard to debian-installer/language (language), debian-installer/country (country), debian-installer/locale (locale) to force your required locale
    – Viperfang
    Feb 19, 2014 at 20:32
  • yes, but would I still be able to boot my USB key for a live-session ?
    – MrVaykadji
    Feb 19, 2014 at 21:19

Persistent live drive

You can use mkusb to create a persistent live drive. It will create 5 partitions. See this link,


  • Partition #1 has the label 'usbdata' and the file system NTFS, which can be used by both Ubuntu and Windows in order to store files and transfer files between computers.

  • The other partitions belong to the Ubuntu persistent live system.

    See this link for more details,


    1. partition: (NTFS) usbdata for storage and transfer of files

    2. partition: GPT: bios_grub flag for booting in BIOS mode; MSDOS: extended partition

    3. partition: (FAT32) boot partition

    4. partition: (ISO 9660) cloned iso file

    5. partition: (ext4) casper-rw or live-rw or persistence


Details about the partitions from and after making the persistent live system:

parted -s "/dev/sdd" print
Model: SanDisk Extreme (scsi)
Disk /dev/sdd: 16,0GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name     Flags
 2      1049kB  2097kB  1049kB               primary  bios_grub
 3      2097kB  258MB   256MB   fat32        primary  boot, esp
 4      258MB   1791MB  1533MB               primary
 5      1791MB  8902MB  7111MB  ext2         primary
 1      8902MB  16,0GB  7111MB  ntfs         primary  msftdata

MODEL            NAME   FSTYPE  LABEL                    MOUNTPOINT  SIZE
Extreme          sdd                                                14,9G
                 |-sdd1 ntfs    usbdata                              6,6G
                 |-sdd2                                                1M
                 |-sdd3 vfat    usbboot                              244M
                 |-sdd4 iso9660 Ubuntu 16.04.1 LTS amd64             1,4G
                 `-sdd5 ext4    casper-rw                            6,6G
 Done :-) 
The target device is ready to use.
was installed

gparted in 16.04 LTS not recognizing iso 9660 file system and bios_grub boot image:

enter image description here

gparted in 17.10 seeing iso 9660 file system and bios_grub boot image:

enter image description here

  • 1
    So basically:: Step 1: mkusb, Step 2: modify usbdata partition as wanted. But I figure there is no way to tell mkusb to not touch certain pre-existing partitions?
    – lucidbrot
    Nov 18, 2021 at 10:12
  • 1
    @lucidbrot, That's right, mkusb grabs the whole drive. If you want something else, you should use another method/tool.
    – sudodus
    Nov 18, 2021 at 10:15
  1. You want to preserve the main part of your USB as FAT32 storage 14GB
  2. You want LiveUSB part in Ext4 2GB

Then the layout of your USB follow:

sdb1 14GB Fat32 storage and EFI folder
sdb2 2GB Ext4 LiveUSB

  1. You have to create the Fat32 part fist to be seen under Windows, as without many tweak, Windows only mount the 1st partition of your USB
  2. This Fat32 partition also hold EFI folder to boot your LiveUSB part
  3. If you want the LiveUSB partition sdb2 on Ext4. By default, the built-in bootx64.efi of the LiveUSB will not boot an Ext4 partition. So I have made a tweaked bootx64.efi. You just copy the file to sdb1/EFI/boot/. And it will boot your Ext4 LiveUSB part. All of my detail here https://github.com/sonvirgo/Ext4-LiveUSB
  • Very interesting. Will this method allow use of a casper-rw partition? Aug 11, 2018 at 18:11
  • @C.S.Cameron Yet, sure. You can add an additional ext4 partition for casper-rw. As far as this still hold: source $prefix/x86_64-efi/grub.cfg so that bootx64.efi can find grub's partition. Update my answer with Windows 10 1703+, you are free to make multiple partitions in any order. All are mountable under 1703+
    – Son Nguyen
    Aug 16, 2018 at 2:45

An easy solution:

  1. Use KDE Partition Manager to delete all partitions and create a 2,048 MB primary partition, FAT32.

  2. Allocate the rest of the free space to your data partition. If you need interoperability with Windows, choose NTFS as the file system, but beware that when read from Linux, all files with have the +x attribute set. Otherwise, choose ext4.

  3. Use unetbootin to write the ISO (Ubuntu 18.04 is about that size, 2GB). Don't worry that it appears to only write to /dev/sda instead of a particular partition.

In my setup, gparted doesn't see the partitions correctly, while KDE Partition Manager does. Not sure what to make of that.

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