Quickly updating a Tails ISO image

... by patching the ISO image file you already have, avoiding downloading the whole new version of this image.

Thanks to the GPG seal published by the Tails project, you will be absolutely sure that the image file thus created is identical to the image published by the Tails project.

Pre-requisites: you MUST have an ISO image file of some previous version of Tails, and also an executable xdelta3.

Details: you will download a VCDIFF patchfile, created by me (using the 'xdelta3' software), which describes the differences between the old version of the Tails image you already have, and the new one.

Usage:

  1. download the GPG seal (.sig) file of the newest Tails ISO image file
  2. download the adequate xdelta3 patchfile. For example the tails-amd64-6.11.iso_to_6.12.xdelta3 patchfile enables you to patch the Tails AMD 6.11 ISO image into a 6.12 version. It is useless if you don't already have the file named tails-amd64-6.11.iso
  3. stop Tails (you will modify the ISO image it uses!)
  4. copy the patchfile into the directory containing your Tails ISO image file
  5. on a command line:
    1. patch your image file by invoking the following 3 commands:
      export Tails_PREVIOUS_VERSION=6.11 # replace '6.11' by the version number of your image
      export Tails_VERSION=6.12 # replace '6.12' by the version number of the newest version
      xdelta3 -d -stails-amd64-${Tails_PREVIOUS_VERSION}.iso tails-amd64-${Tails_PREVIOUS_VERSION}.iso_to_${Tails_VERSION}.xdelta3 tails-amd64-${Tails_VERSION}.iso
    2. check the new image file by invoking: gpg --verify tails-amd64-${Tails_VERSION}.iso.sig. If it does NOT produce a gpg: Good signature from "Tails developers (offline long-term identity key)" message then something failed (it never happened to me nor to numerous friends) and DO NOT USE the new image.