Comment 3 for bug 1872824

Revisiting this as the fix I posted was inaccurate. I did manage to resolve it successfully as I will explain.

I had to manually upgrade the three packages in the dependency chain that was causing the issue like so (order is important):

# keyboard-configuration console-setup-linux console-setup

dpkg -i /path/to/keyboard-configuration_*.deb
dpkg -i /path/to/console-setup-linux_*.deb
dpkg -i /path/to/console-setup_*.deb

I think I ran into other conflicts, but this was the trickiest, as apt always wanted to install them in what appears to be out of the logical dependency order, and would always result in the above error.