Preserving and restoring a snapshot via command line

[dgj]

You may want to try following the commands discussed in this thread (see also comments below):

Update - when to panic?

I was able to reproduce a failed upgrade on a Raspberry Pi 4. The FreedomBox web interface became unavailable, being stuck in the same error loop described above by @Avron. Here’s what you can do if you have SSH or console access: 0. (if you use SSH) install screen, to stay connected even if the SSH session disconnects: sudo apt install -y screen screen [enter, then press space] sudo DEBIAN_FRONTEND=noninteractive apt-get dist-upgrade after the upgrade finished, I ran apt update again, and …

This solved the upgrade issues for me.