How-To Geek

How to Upgrade your Ubuntu ISO Without Re-downloading

Ubuntu 11.04 is finally here and you can’t wait to download it, but as is typical on any Ubuntu release day, the mirrors are crawling. Luckily if you have an old Ubuntu .iso you can update it easily with zsync.

Zsync is a Linux command that allows you to compare an existing .iso with an up-to-date zsync meta file to download only the missing or out of date parts. Combine those parts with your existing file and what you are left with is a completely up to date iso without spending the time to download the entire file.

Just how much bandwidth can this save? In our testing, upgrading an iso from Ubuntu 10.04.2 to 11.04 Beta 2 needed to download about 89% of the original file and 10.10 to 11.04 Beta 2 needed 84%. Obviously the more current the original file is, the less you will need to download.

Install zsync

Although zsync is a native Linux command it still works just as well under Windows with the help of Cygwin. If you need help installing Cygwin in Windows, check out our walk through.

While you are installing Cygwin you will want to make sure you search for zsync on the select packages step.

Zsync is available in the universe repo all the way back to Karmic Koala. So if you are currently using Ubuntu you can install zsync with the normal apt-get command.

sudo apt-get install zsync

Update ISO image

To update your old Ubuntu .iso image, open a command prompt and issue the following command with similar options.

zsync -i /path/to/old/ubuntu.iso http://Path-to-Ubuntu.iso.zsync

This will compare your existing file with the new iso available online, download the missing parts from your current iso, and give you a fully up-to-date new file. Here is an example that lets us update our Ubuntu 10.04.2 image to the latest Ubuntu 11.04.

Note: Using the below command will keep your original Ubuntu 10.04.2 .iso in tact and will create a new Ubuntu 11.04 .iso file.

zsync -i ./ubuntu-10.04.2-desktop-i386.iso

As you can see from the screenshot below, the file we updated with zsync (left) is exactly the same as the original file we downloaded directly (right).

Use the links below for the different zsync files available.

Ubuntu live desktop (with installer) x86 and x86_64

Ubuntu alternate installer x86 and x86_64

Ubuntu server x86 and x86_64

You can also use zsync to change between Ubuntu distributions. Use any of these links for the popular downloads of different Ubuntu flavors.

From our testing, changing from Ubuntu 10.10 to Xubuntu 10.10 required us to download less than half (42%) of the full Xubuntu file.

Kubuntu live desktop (with installer) x86

Note: Kubuntu is only available in DVD form so you will be downloading a significant portion of the DVD image.

Xubuntu live desktop (with installer) x86

Ubuntu Studio live desktop (with installer) x86

Justin Garrison is a Linux and HTPC enthusiast who loves to try new projects. He isn't scared of bricking a cell phone in the name of freedom.

  • Published 04/28/11

Comments (17)

  1. Madhava N

    Very nice tool indeed, well does the same work for Fedora as well.

  2. Ivan Lapis

    Still waiting patiently for the mirrors to update and actually list the files to download…. I CAN’T WAIT FOR THIS!!!!

    However, I might download it through torrent if they have that as an alternate… it can ease the servers some bandwidth from doing a direct download….

  3. Jason Edwards

    I’m really glad you posted this. I updated the 11.04 beta2 image to the latest release. Now I’m going to reboot into the live cd and do an offline update.
    Thanks for this.

  4. Terry Chen

    Great post! I have written a post on this tool in Chinese!
    It is strange that the Natty Chinese Edition was already released yesterday, but I am still waiting for the official edition to come!

  5. Saman

    where we have to put the 10.10 file for sync?! C:?

  6. Jean-Francois Messier

    This sounds like a great tool, especially for those of us who have a download cap.

  7. Mohan

    Wow what an awesome tip!

  8. Marky

    This method of downloading Natty Narwhal would’ve saved me lots of time and bytes but the Ubuntu servers must be under very heavy stress coz I’m getting an error. It can’t connect. :( Too bad. I guess the old torrent way is the only thing reliable for now.

  9. robert

    I never knew this was possible! Awesome tip, will bookmark this page for future reference for sure:-)


  10. Mohamed Muqhtar

    Hi it tried this method but did not get sucess this is what happened in terminal can you help please

    nyumbani@mohamed-nyumbani:~$ zsync -i’/home/nyumbani/ubuntu-10.10-desktop-amd64.iso’
    #################### 100.0% 10.1 kBps DONE

    reading seed file /home/nyumbani/ubuntu-10.10-desktop-amd64.iso: *******************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************Read /home/nyumbani/ubuntu-10.10-desktop-amd64.iso. Target 15.9% complete.
    downloading from
    ###—————– 15.9% 0.0 kBps aborted

    failed to retrieve from ubuntu-11.04-desktop-amd64.iso
    Aborting, download available in ubuntu-11.04-desktop-amd64.iso.part
    verifying download…nyumbani@mohamed-nyumbani:~$

  11. John

    I had no problem downloading Natty Narwhal today. I’m going to install it via bootable USB stick onto an Inspiron Mini 10 netbook that I have. It’s running XP Home now, but I would like to start experimenting with Linux. It seems like a good candidate for the switch because this particular model originally came with the option of Ubuntu factory installed.

  12. Mohamed Muqhtar

    Hi i tried to use this method but it did not work can you help here is what happened in the terminal
    nyumbani@mohamed-nyumbani:~$ zsync -i ‘/home/nyumbani/Downloads/ubuntu-10.10-desktop-amd64.iso’……iso.zsync
    #################### 100.0% 22.7 kBps DONE

    reading seed file /home/nyumbani/Downloads/ubuntu-10.10-desktop-amd64.iso: ********************************************************************************************
    ********************************************************************************Read /home/nyumbani/Downloads/ubuntu-10.10-desktop-amd64.iso. Target 15.9%
    reading seed file ubuntu-11.04-desktop-amd64.iso.part: ********************************************************************************************
    *********************Read ubuntu-11.04-desktop-
    amd64.iso.part. Target 15.9% complete.
    downloading from…..-amd64.iso:
    ###—————– 15.9% 0.0 kBps aborted

    failed to retrieve from ubuntu-11.04-desktop-amd64.iso
    Aborting, download available in ubuntu-11.04-desktop-amd64.iso.part

  13. hotfloppy

    Got the same problem with Mohamed Muqhtar.. :(

  14. Manoj

    It works!!!!!!!!!!!!!!!

    Thanks for posting this. Its very helpful.

  15. Nick S.

    I too received an error trying to update from Natty beta 1 to the final release…

  16. Nick S.

    UPDATE: Using a different mirror resolved my issue.

  17. yussri

    Thanks for this nice tutorials , will this also works with vanilla Ubuntu (customized Ubuntu image ) ?

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