How to do a downgrade in debian after doing "apt-get dist-upgrade -t jessie-backports"

Question

Originally my system was on 8.0 and now it's 8.6 but this latest version does not support all playonlinux requirements to run 86x_64x applications, then I'd like to know if it's possible to safely do a downgrade to my old version 8.0.

Ps: I did nothing with the repositories except adding jessie-backports to sources.list and performing:

sudo apt-get -t jessie-backports dist-upgrade

After that my kernel was also upgraded as well my /etc/os-release status to Debian Jessie 8.6.

Ps2: Would be great to keep my current Os and Kernel versions and also have my playonlinux 32 bits software working, but, if not, going back to my old system version is ok too.

Sorry if this topic was already answered in another question, but I've been searching for that and haven't found it.

Answer 1

You should use 8.6 which is 100% compatible with 8.0. The jessie-backports repo is the one which is not fully compatible, because they're packages from the unstable release called Stretch.

To force downgrade all your packages to Jessie, first make sure you have a rescue disc available. Then create a file: /etc/apt/preferences.d/jessie

Package: *
Pin: release n=jessie
Pin-Priority: 1100

Package: *
Pin: release n=jessie-updates
Pin-Priority: 1100

Start a script session (to record exactly what is happening): script downgrade.log (note this will appear to immediately return—you're actually at a shell prompt inside script, with everything being logged to that file; you'll need a second "exit" to log out). Then do apt-get dist-upgrade. According to quick testing in a VM, this will fail at some point, at which point you'll need to dpkg -i /var/cache/apt/archives/systemd_215*.deb. Then apt-get install -f. Then another apt-get dist-upgrade. You will be asked if you really want to remove the running kernel—unfortunately, you do. Finally, do an apt-get autoremove at the end but take a look at the packages it's removing before saying yes!

Before rebooting, confirm that you have kernel 3.16.0-4 installed. Then reboot.

updates

Answer 2

Boot from a linux live cd and create your chroot environment ( step 1,2 and 3)

Edit your sources.list comment the backports entry then update your system.

Get the list of the backported package and save it :

dpkg -l  |awk '/^ii/ && $3 ~ /bpo[6-8]/ {print $2}' > backports.txt

To keep the current kernel version , edit the backports.txt and remove the kernel package entry e,g:

linux-headers-4.7.0-0.bpo.1-amd64
linux-headers-4.7.0-0.bpo.1-common
linux-image-4.7.0-0.bpo.1-amd64

Purge the packported packages:

sudo apt-get purge $(cat backports.txt) 

Enable backport entry from your sources.list , then run ;

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install $(cat backports.txt)

Maybe you will get a held package , run sudo apt-get -f install

Exit the chroot ( step 6) and reboot your system