diff --git a/app/src/main/java/org/fdroid/fdroid/CleanCacheService.java b/app/src/main/java/org/fdroid/fdroid/CleanCacheService.java
index 1f817f03e..cea679d9f 100644
--- a/app/src/main/java/org/fdroid/fdroid/CleanCacheService.java
+++ b/app/src/main/java/org/fdroid/fdroid/CleanCacheService.java
@@ -47,6 +47,9 @@ public class CleanCacheService extends IntentService {
 
     @Override
     protected void onHandleIntent(Intent intent) {
+        if (intent == null) {
+            return;
+        }
         Process.setThreadPriority(Process.THREAD_PRIORITY_LOWEST);
         Utils.clearOldFiles(Utils.getApkCacheDir(this), Preferences.get().getKeepCacheTime());
         deleteStrayIndexFiles();
diff --git a/app/src/main/java/org/fdroid/fdroid/UpdateService.java b/app/src/main/java/org/fdroid/fdroid/UpdateService.java
index bfe7f1ff8..be0565afa 100644
--- a/app/src/main/java/org/fdroid/fdroid/UpdateService.java
+++ b/app/src/main/java/org/fdroid/fdroid/UpdateService.java
@@ -313,8 +313,12 @@ public class UpdateService extends IntentService {
         Process.setThreadPriority(Process.THREAD_PRIORITY_LOWEST);
 
         final long startTime = System.currentTimeMillis();
-        String address = intent.getStringExtra(EXTRA_ADDRESS);
-        boolean manualUpdate = intent.getBooleanExtra(EXTRA_MANUAL_UPDATE, false);
+        boolean manualUpdate = false;
+        String address = null;
+        if (intent != null) {
+            address = intent.getStringExtra(EXTRA_ADDRESS);
+            manualUpdate = intent.getBooleanExtra(EXTRA_MANUAL_UPDATE, false);
+        }
 
         try {
             // See if it's time to actually do anything yet...
diff --git a/app/src/main/java/org/fdroid/fdroid/net/DownloaderService.java b/app/src/main/java/org/fdroid/fdroid/net/DownloaderService.java
index 8dc833d29..d3e7e6e90 100644
--- a/app/src/main/java/org/fdroid/fdroid/net/DownloaderService.java
+++ b/app/src/main/java/org/fdroid/fdroid/net/DownloaderService.java
@@ -33,7 +33,6 @@ import android.os.Process;
 import android.support.v4.content.IntentCompat;
 import android.support.v4.content.LocalBroadcastManager;
 import android.text.TextUtils;
-import android.util.Log;
 
 import org.fdroid.fdroid.ProgressListener;
 import org.fdroid.fdroid.Utils;
@@ -46,9 +45,14 @@ import java.net.URL;
 /**
  * DownloaderService is a service that handles asynchronous download requests
  * (expressed as {@link Intent}s) on demand.  Clients send download requests
- * through {@link android.content.Context#startService(Intent)} calls; the
- * service is started as needed, handles each Intent in turn using a worker
- * thread, and stops itself when it runs out of work.
+ * through {@link #queue(Context, String)} calls.  The
+ * service is started as needed, it handles each {@code Intent} using a worker
+ * thread, and stops itself when it runs out of work.  Requests can be canceled
+ * using {@link #cancel(Context, String)}.  If this service is killed during
+ * operation, it will receive the queued {@link #queue(Context, String)} and
+ * {@link #cancel(Context, String)} requests again due to
+ * {@link Service#START_REDELIVER_INTENT}.  Bad requests will be ignored,
+ * including on restart after killing via {@link Service#START_NOT_STICKY}.
  * <p>
  * This "work queue processor" pattern is commonly used to offload tasks
  * from an application's main thread.  The DownloaderService class exists to
@@ -112,10 +116,15 @@ public class DownloaderService extends Service {
     @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
         Utils.debugLog(TAG, "Received Intent for downloading: " + intent + " (with a startId of " + startId + ")");
+
+        if (intent == null) {
+            return START_NOT_STICKY;
+        }
+
         String uriString = intent.getDataString();
         if (uriString == null) {
-            Log.e(TAG, "Received Intent with no URI: " + intent);
-            return START_STICKY;
+            Utils.debugLog(TAG, "Received Intent with no URI: " + intent);
+            return START_NOT_STICKY;
         }
 
         if (ACTION_CANCEL.equals(intent.getAction())) {
@@ -128,7 +137,7 @@ public class DownloaderService extends Service {
             } else if (isActive(uriString)) {
                 downloader.cancelDownload();
             } else {
-                Log.e(TAG, "ACTION_CANCEL called on something not queued or running (expected to find message with ID of " + whatToRemove + " in queue).");
+                Utils.debugLog(TAG, "ACTION_CANCEL called on something not queued or running (expected to find message with ID of " + whatToRemove + " in queue).");
             }
         } else if (ACTION_QUEUE.equals(intent.getAction())) {
             Message msg = serviceHandler.obtainMessage();
@@ -138,7 +147,7 @@ public class DownloaderService extends Service {
             serviceHandler.sendMessage(msg);
             Utils.debugLog(TAG, "Queued download of " + uriString);
         } else {
-            Log.e(TAG, "Received Intent with unknown action: " + intent);
+            Utils.debugLog(TAG, "Received Intent with unknown action: " + intent);
         }
 
         return START_REDELIVER_INTENT; // if killed before completion, retry Intent
diff --git a/app/src/main/java/org/fdroid/fdroid/net/WifiStateChangeService.java b/app/src/main/java/org/fdroid/fdroid/net/WifiStateChangeService.java
index 3bf597d8f..69a41761d 100644
--- a/app/src/main/java/org/fdroid/fdroid/net/WifiStateChangeService.java
+++ b/app/src/main/java/org/fdroid/fdroid/net/WifiStateChangeService.java
@@ -56,6 +56,10 @@ public class WifiStateChangeService extends IntentService {
     @Override
     protected void onHandleIntent(Intent intent) {
         android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_LOWEST);
+        if (intent == null) {
+            Utils.debugLog(TAG, "received null Intent, ignoring");
+            return;
+        }
         Utils.debugLog(TAG, "WiFi change service started, clearing info about wifi state until we have figured it out again.");
         NetworkInfo ni = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
         wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);
@@ -188,7 +192,11 @@ public class WifiStateChangeService extends IntentService {
 
     private void setIpInfoFromNetworkInterface() {
         try {
-            for (Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces(); networkInterfaces.hasMoreElements();) {
+            Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces();
+            if (networkInterfaces == null) {
+                return;
+            }
+            while (networkInterfaces.hasMoreElements()) {
                 NetworkInterface netIf = networkInterfaces.nextElement();
 
                 for (Enumeration<InetAddress> inetAddresses = netIf.getInetAddresses(); inetAddresses.hasMoreElements();) {