I'm trying to turn live USB into live USB with persistent memory. I'm following this procedure. The procedure says to "Add a Space and persistent after quiet splash --- in the following files" and specifies three files:




The problem is that I cannot find those files.

Any suggestion what to do?

Additional information:

Operating system: Ubuntu 18.04.2 LTS


Different setup - live-persistent; missing files?? This is live-persistent setup on different USB pendrive and that works just fine. But neither of the files are there.

Different setup - live-persistent; missing files??

  • I'd check again to make sure that you've accurately and completely completed the prerequisite steps in the answer you linked.
    – Nmath
    Nov 10, 2022 at 22:24
  • look at ventoy persistence ventoy.net/en/plugin_persistence.html
    – lnee
    Nov 10, 2022 at 22:28
  • But it IS persistent by default now, isn’t it ? I remember having discovered a few years ago that upon boot, it checks for free unpartitioned space on the boot device and if there’s some, it automatically creates a new partition for persistent memory. I was outraged, since I consider a live system should never have a write behaviour by default, and reported a bug on launchpad, but the developer at the time “really wanted” to do that, and clearly intended to disregard my arguments no matter what. So while I’m outraged, you at least should be happy :)
    – NovHak
    Nov 10, 2022 at 23:01
  • 2
    You've provided no OS/release details, as releases since 20.10 have varied slightly compared to prior releases so are you following instructions that match your OS/release? Persistence is automatically dealt with using various tools (that get updated to deal with changes in Ubuntu ISOs, which from 20.10 have varied so all platforms are identical as Ubuntu is built for many architectures including s390, armhf, arm64, ppc64el... and not just amd64) so provide OS/release details. mkusb is TESTED for all releases & works if using an updated version that copes with the release being used.
    – guiverc
    Nov 11, 2022 at 2:10
  • @BlueSkies: I will try to remember to update that post to also suit version 22.04. I believe Isolinux has not been used since 19.10. If you are using a later version of Ubuntu, edit /boot/grub/grub.cfg placing the word persistent one space after file=/cdrom/preseed/ubuntu.seed in the first menuentry. Let me know if this works for you. Nov 11, 2022 at 12:22

1 Answer 1


Changing Live Pendrive to Persistent Pendrive

This works both with BIOS and UEFI.

Many people prefer a Persistent Pendrive that will save changes;

  • Create a Live Pendrive using Rufus or similar;

  • Boot the pendrive toram to make the drive editable:

    Press Shift when booting; press Esc from Language; press F6; press Esc;

    Type a Space and toram after quiet splash ---, and press Enter.

  • Create a casper-rw file:

    sudo dd if=/dev/zero of=casper-rw bs=1M count=512

    sudo mkfs.ext3 -L casper-rw -F casper-rw

(where count=512 is the persistence size in megabytes, with a max of 4GB).

  • Move the new casper-rw file from home to the root of the Live Pendrive;

  • Add a Space and persistent after quiet splash --- in the following files, (pre-22.04):

    /isolinux/txt.cfg, (for BIOS boot persistence Rufus);

    /syslinux.cfg, (for BIOS boot persistence UNetbootin);

    /boot/grub/grub.cfg, (for UEFI boot persistence).

enter image description here File location 20.04 and prior.

  • In Ubuntu 22.04 and later add the word persistent one space after file=/cdrom/preseed/ubuntu.seed in grub.cfg.

enter image description here File location 22.04 and later.

  • Shut down and reboot the persistent drive.

It's also possible to turn a Live USB into a Full-Install USB which has some advantages, except it won't install Ubuntu: Can Ubuntu be installed to the pendrive it was booted from?

Nowadays some Live Ubuntu apps will create Live Persistent USB's, Rufus, Ventoy, mkusb and Universal. Others like Startup Disk Creator, dd, Gnome-Disks and Etcher create ISO9660 based USB and are difficult to make persistent.

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