>> I'll attempt to recover with a live cd and can post updates here if that's >> useful. > chroot and run ldconfig, for a start. Thanks for the suggestion. I ended up doing something similar in parallel (apologies for ubuntu-specific instructions):
1. boot into the live cd (I used ubuntu 18.04) 2. mount the hard drive (the live cd's graphical session also supports encrypted drives) 3. copy the live cd's libcrypt.so.1 to the mounted hard drive 4. boot into normal (ie. not live cd) recovery mode and select the dpkg option. The configure step now completes without issue 5. boot normally I don't think there's any remaining artefacts: dpkg also replaced the temporary libcrypt.so.1 with the symlink that it's supposed to be.
