diff --git a/auto-upgrade.nix b/auto-upgrade.nix
index 20e74fa..18753ae 100644
--- a/auto-upgrade.nix
+++ b/auto-upgrade.nix
@@ -57,9 +57,9 @@ let cfg = config.system.autoUpgrade; in
         default = false;
         type = types.bool;
         description = ''
-          Shall the system be rebooted if the new configuration
-          uses a different kernel, kernel modules or initrd
-          than the booted system?
+          Reboot the system into the new generation instead of a switch
+          if the new generation uses a different kernel, kernel modules
+          or initrd than the booted system.
         '';
       };
 
@@ -88,29 +88,25 @@ let cfg = config.system.autoUpgrade; in
           HOME = "/root";
         } // config.networking.proxy.envVars;
 
-      path = [ pkgs.gnutar pkgs.xz.bin pkgs.gitMinimal config.nix.package.out ];
+      path = [ pkgs.coreutils pkgs.gnutar pkgs.xz.bin pkgs.gitMinimal config.nix.package.out ];
 
-      script = ''
-        ${lib.optionalString cfg.allowReboot ''
-          set -euo pipefail
-          T=$(mktemp -d)
-          cd "$T"
-          ${config.system.build.nixos-rebuild}/bin/nixos-rebuild build ${toString cfg.flags}
-          booted="$(${pkgs.coreutils}/bin/readlink /run/booted-system/{initrd,kernel,kernel-modules})"
-          built="$(${pkgs.coreutils}/bin/readlink result/{initrd,kernel,kernel-modules})"
-          cd /tmp
-          rm -rf "$T"
-          if [ "$booted" = "$built" ]; then
-            ${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch ${toString cfg.flags}
-          else
-            ${config.system.build.nixos-rebuild}/bin/nixos-rebuild boot ${toString cfg.flags}
-            /run/current-system/sw/bin/shutdown -r +1
-          fi
-          ''}
-          ${lib.optionalString (!cfg.allowReboot) "${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch ${toString cfg.flags}"}
+      script = let
+          nixos-rebuild = "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
+        in
+        if cfg.allowReboot then ''
+            ${nixos-rebuild} boot ${toString cfg.flags}
+            booted="$(readlink /run/booted-system/{initrd,kernel,kernel-modules})"
+            built="$(readlink /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
+            if [ "$booted" = "$built" ]; then
+              ${nixos-rebuild} switch ${toString cfg.flags}
+            else
+              /run/current-system/sw/bin/shutdown -r +1
+            fi
+          '' else ''
+            ${nixos-rebuild} switch ${toString cfg.flags}
         '';
 
-      startAt = optional cfg.enable cfg.dates;
+      startAt = cfg.dates;
     };
 
   };