diff --git a/src/com/android/settings/notification/AppNotificationSettings.java b/src/com/android/settings/notification/AppNotificationSettings.java
index efa43cd033c..050008de0af 100644
--- a/src/com/android/settings/notification/AppNotificationSettings.java
+++ b/src/com/android/settings/notification/AppNotificationSettings.java
@@ -39,6 +39,7 @@ import android.widget.Toast;
 import com.android.internal.widget.LockPatternUtils;
 import com.android.settings.R;
 import com.android.settings.SettingsPreferenceFragment;
+import com.android.settings.Utils;
 import com.android.settings.notification.NotificationAppList.AppRow;
 import com.android.settings.notification.NotificationAppList.Backend;
 
@@ -184,6 +185,12 @@ public class AppNotificationSettings extends SettingsPreferenceFragment {
                 }
             });
         }
+
+        // Users cannot block notifications from system/signature packages
+        if (Utils.isSystemPackage(pm, info)) {
+            getPreferenceScreen().removePreference(mBlock);
+            mPriority.setDependency(null); // don't have it depend on a preference that's gone
+        }
     }
 
     private void toastAndFinish() {
@@ -199,7 +206,7 @@ public class AppNotificationSettings extends SettingsPreferenceFragment {
                 final String p = packages[i];
                 if (pkg.equals(p)) {
                     try {
-                        return pm.getPackageInfo(pkg, 0);
+                        return pm.getPackageInfo(pkg, PackageManager.GET_SIGNATURES);
                     } catch (NameNotFoundException e) {
                         Log.w(TAG, "Failed to load package " + pkg, e);
                     }
diff --git a/src/com/android/settings/notification/NotificationAppList.java b/src/com/android/settings/notification/NotificationAppList.java
index 7ca4b18136b..ad6956bd6c1 100644
--- a/src/com/android/settings/notification/NotificationAppList.java
+++ b/src/com/android/settings/notification/NotificationAppList.java
@@ -351,7 +351,6 @@ public class NotificationAppList extends PinnedHeaderListFragment
         public boolean priority;
         public boolean sensitive;
         public boolean first;  // first app in section
-        public boolean isSystem;
     }
 
     private static final Comparator<AppRow> mRowComparator = new Comparator<AppRow>() {
@@ -377,7 +376,6 @@ public class NotificationAppList extends PinnedHeaderListFragment
         row.banned = backend.getNotificationsBanned(row.pkg, row.uid);
         row.priority = backend.getHighPriority(row.pkg, row.uid);
         row.sensitive = backend.getSensitive(row.pkg, row.uid);
-        row.isSystem = Utils.isSystemPackage(pm, pkg);
         return row;
     }