diff --git a/config/services/hydra/nix-config.nix b/config/services/hydra/nix-config.nix
index c9e1177..c7aa778 100644
--- a/config/services/hydra/nix-config.nix
+++ b/config/services/hydra/nix-config.nix
@@ -5,7 +5,7 @@
       sshUser = "hydra-queue-runner";
       maxJobs = 40;
       speedFactor = 40;
-      systems = [ "x86_64-linux" "x86_64-darwin" ];
+      systems = [ "x86_64-linux" ];
       supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
       sshKey = "/var/lib/hydra/id_ed25519";
     }
@@ -14,7 +14,7 @@
       sshUser = "build";
       maxJobs = 4;
       speedFactor = 8;
-      systems = [ "aarch64-linux" "aarch64-darwin" ];
+      systems = [ "aarch64-linux" ];
       supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
       sshKey = "/var/lib/hydra/id_ed25519";
     }
diff --git a/pkgs/upgrade-system/upgrade-system.sh b/pkgs/upgrade-system/upgrade-system.sh
index cb5d43d..086bc1b 100644
--- a/pkgs/upgrade-system/upgrade-system.sh
+++ b/pkgs/upgrade-system/upgrade-system.sh
@@ -2,6 +2,21 @@
 
 set -euo pipefail
 
+ALLOW_REBOOT=
+
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    --allow-reboot)
+      ALLOW_REBOOT=1
+      shift
+    ;;
+    *)
+      echo "Unknown option $1"
+      exit 1
+    ;;
+  esac
+done
+
 HYDRA_URL="https://hydra.kyouma.net/job/infra/nixfiles/nixosConfigurations.${HOSTNAME}/latest-finished"
 
 NEW_STORE_PATH="$(curl --fail -s -L -H "Accept: application/json" "${HYDRA_URL}" | jq -r ".buildoutputs.out.path")"
@@ -44,9 +59,14 @@ echo "Set new profile as boot target"
 nixos-needsreboot
 
 if [[ -f "/var/run/reboot-required" ]]; then
-  delay=$(echo -n $RANDOM | tail -c 2)
-  echo "Rebooting system in ${delay} Minutes"
-  shutdown -r +"${delay}"
+  if [[ -n "$ALLOW_REBOOT" ]]; then
+    delay=$(echo -n $RANDOM | tail -c 2)
+    echo "Rebooting system in ${delay} Minutes"
+    shutdown -r +"${delay}"
+  else
+    echo "Unattended reboot not allowed"
+    echo "Reboot system manually"
+  fi
 else
   echo "Activating system now"
   /nix/var/nix/profiles/system/bin/switch-to-configuration switch