To get a Stage 1 shell:

Add "debug1" to the kernel command line.


Switching to maintenance mode:

$ shutdown now

To get out of maintenance mode:

$ initctl emit startup 


Updating the current system configuration:

$ nix-env -p /nix/var/nix/profiles/system -f system-configuration.nix -i -A systemConfiguration
$ /nix/var/nix/profiles/system/bin/switch-to-configuration