I believe I experienced the same, with root cause a lack of free space in /boot. After the upgrade failed with errors, but _before_ attempting a reboot, my workaround was:
apt autoremove mkdir /boot_moved_20201011 mv initrd.img-4.15.0-118-generic /boot_moved_20201011/ apt-get upgrade mv /boot_moved_20201011/initrd.img-4.15.0-118-generic . #reboot -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1897747 Title: package initramfs-tools 0.136ubuntu6.3 failed to install/upgrade: installed initramfs-tools package post-installation script subprocess returned error exit status 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1897747/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
