diff --git a/app/src/full/java/a/a.java b/app/src/full/java/a/a.java
index e2481e07e..b97ad15e2 100644
--- a/app/src/full/java/a/a.java
+++ b/app/src/full/java/a/a.java
@@ -1,10 +1,13 @@
 package a;
 
 import com.topjohnwu.core.utils.BootSigner;
+import com.topjohnwu.magisk.utils.PatchAPK;
 
 import androidx.annotation.Keep;
 
 @Keep
 public class a extends BootSigner {
-    /* stub */
+    public static boolean patchAPK(String in, String out, String pkg) {
+        return PatchAPK.patch(in, out, pkg);
+    }
 }
diff --git a/app/src/full/java/com/topjohnwu/magisk/utils/DownloadApp.java b/app/src/full/java/com/topjohnwu/magisk/utils/DownloadApp.java
index f08090f30..9436f6897 100644
--- a/app/src/full/java/com/topjohnwu/magisk/utils/DownloadApp.java
+++ b/app/src/full/java/com/topjohnwu/magisk/utils/DownloadApp.java
@@ -19,6 +19,8 @@ import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileOutputStream;
 
+import dalvik.system.DexClassLoader;
+
 public class DownloadApp {
 
     public static void upgrade(String name) {
@@ -72,10 +74,16 @@ public class DownloadApp {
                 progress.update();
                 patched = new File(apk.getParent(), "patched.apk");
                 try {
-                    JarMap jarMap = PatchAPK.patch(apk.getPath(), app.getPackageName());
-                    SignAPK.sign(jarMap, new BufferedOutputStream(new FileOutputStream(patched)));
+                    // Try using the new APK to patch itself
+                    ClassLoader loader = new DexClassLoader(apk.getPath(),
+                            apk.getParent(), null, ClassLoader.getSystemClassLoader());
+                    loader.loadClass("a.a")
+                            .getMethod("patchAPK", String.class, String.class, String.class)
+                            .invoke(null, apk.getPath(), patched.getPath(), app.getPackageName());
                 } catch (Exception e) {
-                    return;
+                    e.printStackTrace();
+                    // Fallback to use the current implementation
+                    PatchAPK.patch(apk.getPath(), patched.getPath(), app.getPackageName());
                 }
             }
             APKInstall.install(app, patched);
diff --git a/app/src/full/java/com/topjohnwu/magisk/utils/PatchAPK.java b/app/src/full/java/com/topjohnwu/magisk/utils/PatchAPK.java
index c8bd1d32c..17ca8d9b0 100644
--- a/app/src/full/java/com/topjohnwu/magisk/utils/PatchAPK.java
+++ b/app/src/full/java/com/topjohnwu/magisk/utils/PatchAPK.java
@@ -102,14 +102,8 @@ public class PatchAPK {
         File repack = new File(app.getFilesDir(), "patched.apk");
         String pkg = genPackageName("com.", BuildConfig.APPLICATION_ID.length());
 
-        try {
-            JarMap apk;
-            if ((apk = patch(app.getPackageCodePath(), pkg)) == null)
-                return false;
-            SignAPK.sign(apk, new BufferedOutputStream(new FileOutputStream(repack)));
-        } catch (Exception e) {
+        if (!patch(app.getPackageCodePath(), repack.getPath(), pkg))
             return false;
-        }
 
         // Install the application
         repack.setReadable(true, false);
@@ -123,23 +117,24 @@ public class PatchAPK {
         return true;
     }
 
-    public static JarMap patch(String apk, String pkg) {
+    public static boolean patch(String in, String out, String pkg) {
         try {
-            JarMap jar = new JarMap(apk);
+            JarMap jar = new JarMap(in);
             JarEntry je = jar.getJarEntry(Const.ANDROID_MANIFEST);
             byte xml[] = jar.getRawData(je);
 
             if (!findAndPatch(xml, BuildConfig.APPLICATION_ID, pkg) ||
                     !findAndPatch(xml, R.string.app_name, R.string.re_app_name))
-                return null;
+                return false;
 
             // Write in changes
             jar.getOutputStream(je).write(xml);
-            return jar;
+            SignAPK.sign(jar, new BufferedOutputStream(new FileOutputStream(out)));
         } catch (Exception e) {
             e.printStackTrace();
-            return null;
+            return false;
         }
+        return true;
     }
 
     public static void hideManager() {