Error when running nixos-rebuild for a microvm

packages.nix

@@ -111,9 +111,16 @@ lib.attrsets.mapAttrs
         # remote machine and bulding and switching there.
         # Can be run with `nix run c3d2#…-nixos-rebuild switch`
         "${name}-nixos-rebuild" = pkgs.writeScriptBin "${name}-nixos-rebuild" ''
-          #!${pkgs.runtimeShell} -ex
+          #!${pkgs.runtimeShell} -e
+
+          if nix eval .#nixosConfigurations.${name}.config.c3d2.deployment.server &>/dev/null; then
+            echo "microvms cannot be updated with nixos-rebuild. Use nix run .#microvm-update-${name}"
+            exit 2
+          fi
+
           [[ $(ssh ${target} cat /etc/hostname) == ${name} ]]
           nix copy --no-check-sigs --to ssh-ng://${target} ${inputPaths}
+
           # use nixos-rebuild from target config
           nixosRebuild=$(nix build ${self}#nixosConfigurations.${name}.config.system.build.nixos-rebuild --no-link --json | ${pkgs.jq}/bin/jq -r '.[0].outputs.out')
           nix copy --no-check-sigs --to ssh-ng://${target} $nixosRebuild