This is something to do with linux 5 kernel api You need to manually downgrade systemd - well - that's what I did.
when you boot with grub or refind - edit default entry and change the init=/bin/init to init=/bin/bash That will bypass systemd starting up and drop you straight into a shell. mount -o remount / mount /usr mount /var mount /dev/sdc1 /mnt dpkg -i /mnt/systemd_241-7~deb10u3_amd64.deb On a system that works or download a previous version somehow. dpkg -l systemd Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Architecture Description +++-==============-============-============-================================= ii systemd 245.5-2 amd64 system and service manager root@leet:/home/wozza# apt-cache policy systemd systemd: Installed: 245.5-2 Candidate: 245.5-2 Version table: *** 245.5-2 500 500 http://ftp.iinet.net.au/debian/debian bullseye/main amd64 Packages 100 /var/lib/dpkg/status 241-7~deb10u3 500 500 http://ftp.iinet.net.au/debian/debian stable/main amd64 Packages root@leet:/home/wozza# apt-get download systemd=241-7~deb10u3 Get:1 http://ftp.iinet.net.au/debian/debian stable/main amd64 systemd amd64 241-7~deb10u3 [3,495 kB] Fetched 3,495 kB in 11s (321 kB/s) W: Download is performed unsandboxed as root as file '/home/wozza/systemd_241-7~deb10u3_amd64.deb' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied) root@leet:/home/wozza# ll systemd_241-7~deb10u3_amd64.deb -rw-r--r-- 1 root root 3495428 Jan 31 15:11 systemd_241-7~deb10u3_amd64.deb root@leet:/home/wozza# mount /dev/sdc1 /mnt root@leet:/home/wozza# cp systemd_241-7~deb10u3_amd64.deb /mnt/ root@leet:/home/wozza# cd /mnt/ root@leet:/mnt# mkdir unpack root@leet:/mnt# cd unpack/ root@leet:/mnt/unpack# dpkg-deb -R ../systemd_241-7~deb10u3_amd64.deb . worst comes to worse can copy the files across from unpack directory - good luck. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1876486 Title: Kernel panic booting after 18.04 to 20.04 upgrade To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libseccomp/+bug/1876486/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs