I had had bad times while installing Flash Player on this beautiful Linux distribution. I understand concern of Debian community, and I strongly agree that close-source codes need to be away from these distributions.

If you have needed to run Adobe Flash Player on any kind of Debian distribution, you can use this post to install Flash Player, but I want to remind you that you should not use Adobe Flash Player after December 31, 2020 because it will not get any security patches1.

Also, I want to remind you that I am using Firefox ESR version 60.9.0 while writing this post.

Firefox 68 ESR released, and this post can still be applied for it

Installation of Adobe Flash Player

Before get started, cd(1) to either /tmp or some type of temporary directory. In this post, I use /tmp.

We need to download Flash Player from its source. The downloaded file is a gziped tarball

wget https://fpdownload.adobe.com/get/flashplayer/pdc/32.0.0.270/flash_player_npapi_linux.x86_64.tar.gz

Now, we need to extract with tar(1)

tar -xf flash_player_npapi_linux.x86_64.tar.gz libflashplayer.so

Create a directory to place libflashplayer.so file. I will mkdir the directory under /usr/lib as flashplugin-nonfree. This is because I want to easily update without messing with system libraries. Also, I can place a README about procedures I need to take in order to update Flash Player version

mkdir /usr/lib/flashplugin-nonfree

We can mv(1) libflashplayer.so under /usr/lib/flashplugin-nonfree directory. Also, I would remind you that do not forget change owner and file permisions

mv libflashplayer.so /usr/lib/flashplugin-nonfree

chmod 644 /usr/lib/flashplugin-nonfree/libflashplayer.so
chown root:root /usr/lib/flashplugin-nonfree/libflashplayer.so

Here is the interesting part because I had not used update-alternatives(1) before, and when I used in this installation, I found its magic. I always use ln(1) to create symlinks, but update-alternatives(1) provides an “User Interface” to control, create and manage symlinks

update-alternatives --quiet --install \
   /usr/lib/mozilla/plugins/flash-mozilla.so \
   flash-mozilla.so \
   /usr/lib/flashplugin-nonfree/libflashplayer.so 50

You can list symlinks that are created by update-alternatives(1) with --list flag

update-alternatives --list flash-mozilla.so

Now, all you need is to restart your Firefox and you should see the changes immediately. If not, restart the system. Otherwise, I don’t know; it worked on my machine.

Conclusion

If you have a situation like mine, having Flash Player just for an old system, you will likely install it with pain, but this post may help you in this road. I would thank for Patrick2 and Greg3 for their explanation.

  1. https://helpx.adobe.com/shockwave/shockwave-end-of-life-faq.html ↩

  2. https://unix.stackexchange.com/a/388266 ↩

  3. https://lists.debian.org/debian-user/2019/10/msg00837.html ↩