diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index cea3a868..454b21a1 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -7,7 +7,6 @@
     <uses-permission android:name="android.permission.REBOOT" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.RECOVERY" />
-    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
diff --git a/res/values/strings.xml b/res/values/strings.xml
index fa83f06d..2205c688 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -49,7 +49,6 @@
     <string name="finalizing_package">Finalizing package installation</string>
     <string name="preparing_ota_first_boot">Preparing for first boot</string>
     <string name="dialog_prepare_zip_message">Preliminary update preparation</string>
-    <string name="notification_prepare_zip_error_title">Could not prepare update</string>
 
     <string name="reboot">Reboot</string>
 
diff --git a/src/org/lineageos/updater/UpdatesListAdapter.java b/src/org/lineageos/updater/UpdatesListAdapter.java
index aee52c3f..5b0705ec 100644
--- a/src/org/lineageos/updater/UpdatesListAdapter.java
+++ b/src/org/lineageos/updater/UpdatesListAdapter.java
@@ -160,7 +160,8 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
             viewHolder.mProgressPercentage.setText(percentage);
         } else if (mUpdaterController.isInstallingUpdate(downloadId)) {
             setButtonAction(viewHolder.mAction, Action.CANCEL_INSTALLATION, downloadId, true);
-            viewHolder.mProgressText.setText(
+            boolean notAB = !mUpdaterController.isInstallingABUpdate();
+            viewHolder.mProgressText.setText(notAB ? R.string.dialog_prepare_zip_message :
                     update.getFinalizing() ?
                             R.string.finalizing_package :
                             R.string.preparing_ota_first_boot);
diff --git a/src/org/lineageos/updater/controller/Controller.java b/src/org/lineageos/updater/controller/Controller.java
index 3daead24..fb6df395 100644
--- a/src/org/lineageos/updater/controller/Controller.java
+++ b/src/org/lineageos/updater/controller/Controller.java
@@ -53,4 +53,6 @@ public interface Controller {
     boolean isInstallingUpdate(String downloadId);
 
     boolean isInstallingUpdate();
+
+    boolean isInstallingABUpdate();
 }
diff --git a/src/org/lineageos/updater/controller/UpdateInstaller.java b/src/org/lineageos/updater/controller/UpdateInstaller.java
new file mode 100644
index 00000000..f0d41c95
--- /dev/null
+++ b/src/org/lineageos/updater/controller/UpdateInstaller.java
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2017 The LineageOS Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.lineageos.updater.controller;
+
+import android.content.Context;
+import android.os.SystemClock;
+import android.support.v7.preference.PreferenceManager;
+import android.util.Log;
+
+import org.lineageos.updater.misc.Constants;
+import org.lineageos.updater.misc.FileUtils;
+import org.lineageos.updater.misc.Utils;
+import org.lineageos.updater.model.UpdateInfo;
+import org.lineageos.updater.model.UpdateStatus;
+
+import java.io.File;
+import java.io.IOException;
+
+class UpdateInstaller {
+
+    private static final String TAG = "UpdateInstaller";
+
+    private static Thread sPrepareUpdateThread;
+    private static boolean sCancelled;
+
+    private final Context mContext;
+    private final UpdaterController mUpdaterController;
+
+    UpdateInstaller(Context context, UpdaterController controller) {
+        mContext = context;
+        mUpdaterController = controller;
+    }
+
+    static boolean isInstalling() {
+        return !sCancelled && sPrepareUpdateThread != null;
+    }
+
+    static boolean isInstalling(String downloadId) {
+        return !sCancelled && sPrepareUpdateThread != null &&
+                downloadId.equals(sPrepareUpdateThread.getName());
+    }
+
+    void install(String downloadId) {
+        UpdateInfo update = mUpdaterController.getUpdate(downloadId);
+        boolean deleteUpdate = PreferenceManager.getDefaultSharedPreferences(mContext)
+                .getBoolean(Constants.PREF_AUTO_DELETE_UPDATES, false);
+        if (deleteUpdate) {
+            // Renaming the file is enough to have it deleted automatically
+            File uncrytpFile = new File(
+                    update.getFile().getAbsolutePath() + Constants.UNCRYPT_FILE_EXT);
+            update.getFile().renameTo(uncrytpFile);
+            installPackage(uncrytpFile, downloadId);
+        } else if (Utils.isEncrypted(mContext, update.getFile())) {
+            // uncrypt rewrites the file so that it can be read without mounting
+            // the filesystem, so create a copy of it.
+            prepareForUncryptAndInstall(update);
+        } else {
+            installPackage(update.getFile(), downloadId);
+        }
+    }
+
+    private void installPackage(File update, String downloadId) {
+        try {
+            android.os.RecoverySystem.installPackage(mContext, update);
+        } catch (IOException e) {
+            // TODO: show error message
+            Log.e(TAG, "Could not install update", e);
+        }
+    }
+
+    private void prepareForUncryptAndInstall(UpdateInfo update) {
+        if (sPrepareUpdateThread != null) {
+            Log.e(TAG, "Already preparing an update");
+            return;
+        }
+
+        String uncryptFilePath = update.getFile().getAbsolutePath() + Constants.UNCRYPT_FILE_EXT;
+        File uncryptFile = new File(uncryptFilePath);
+
+        Runnable copyUpdateRunnable = new Runnable() {
+            private long mLastUpdate = -1;
+
+            FileUtils.ProgressCallBack mProgressCallBack = new FileUtils.ProgressCallBack() {
+                @Override
+                public void update(int progress) {
+                    long now = SystemClock.elapsedRealtime();
+                    if (mLastUpdate < 0 || now - mLastUpdate > 500) {
+                        mUpdaterController.getActualUpdate(update.getDownloadId())
+                                .setInstallProgress(progress);
+                        mUpdaterController.notifyInstallProgress(update.getDownloadId());
+                        mLastUpdate = now;
+                    }
+                }
+            };
+
+            @Override
+            public void run() {
+                try {
+                    FileUtils.copyFile(update.getFile(), uncryptFile, mProgressCallBack);
+
+                    // Use INSTALLATION_CANCELLED to clear everything.
+                    // This shouldn't really matter in case of success.
+                    mUpdaterController.getActualUpdate(update.getDownloadId())
+                            .setStatus(UpdateStatus.INSTALLATION_CANCELLED);
+                    mUpdaterController.getActualUpdate(update.getDownloadId())
+                            .setInstallProgress(0);
+                    mUpdaterController.notifyUpdateChange(update.getDownloadId());
+
+                    if (!sPrepareUpdateThread.isInterrupted()) {
+                        installPackage(uncryptFile, update.getDownloadId());
+                    } else {
+                        uncryptFile.delete();
+                    }
+                } catch (IOException e) {
+                    Log.e(TAG, "Could not copy update", e);
+                    uncryptFile.delete();
+                    mUpdaterController.getActualUpdate(update.getDownloadId())
+                            .setStatus(UpdateStatus.INSTALLATION_FAILED);
+                    mUpdaterController.notifyUpdateChange(update.getDownloadId());
+                } finally {
+                    sPrepareUpdateThread = null;
+                }
+            }
+        };
+
+        sPrepareUpdateThread = new Thread(copyUpdateRunnable);
+        sPrepareUpdateThread.setName(update.getDownloadId());
+        sPrepareUpdateThread.start();
+        sCancelled = false;
+
+        mUpdaterController.getActualUpdate(update.getDownloadId())
+                .setStatus(UpdateStatus.INSTALLING);
+        mUpdaterController.notifyUpdateChange(update.getDownloadId());
+    }
+
+    public void cancel() {
+        if (sCancelled || sPrepareUpdateThread == null) {
+            Log.d(TAG, "Nothing is being copied");
+            return;
+        }
+        sCancelled = true;
+        sPrepareUpdateThread.interrupt();
+    }
+}
diff --git a/src/org/lineageos/updater/controller/UpdaterController.java b/src/org/lineageos/updater/controller/UpdaterController.java
index 9efa8e5d..d6ed4016 100644
--- a/src/org/lineageos/updater/controller/UpdaterController.java
+++ b/src/org/lineageos/updater/controller/UpdaterController.java
@@ -534,11 +534,18 @@ public class UpdaterController implements Controller {
 
     @Override
     public boolean isInstallingUpdate() {
-        return ABUpdateInstaller.isInstallingUpdate(mContext);
+        return UpdateInstaller.isInstalling() ||
+                ABUpdateInstaller.isInstallingUpdate(mContext);
     }
 
     @Override
     public boolean isInstallingUpdate(String downloadId) {
-        return ABUpdateInstaller.isInstallingUpdate(mContext, downloadId);
+        return UpdateInstaller.isInstalling(downloadId) ||
+                ABUpdateInstaller.isInstallingUpdate(mContext, downloadId);
+    }
+
+    @Override
+    public boolean isInstallingABUpdate() {
+        return ABUpdateInstaller.isInstallingUpdate(mContext);
     }
 }
diff --git a/src/org/lineageos/updater/controller/UpdaterService.java b/src/org/lineageos/updater/controller/UpdaterService.java
index 58df987e..03fcf8d3 100644
--- a/src/org/lineageos/updater/controller/UpdaterService.java
+++ b/src/org/lineageos/updater/controller/UpdaterService.java
@@ -27,7 +27,6 @@ import android.os.Bundle;
 import android.os.IBinder;
 import android.support.v4.content.LocalBroadcastManager;
 import android.support.v7.app.NotificationCompat;
-import android.support.v7.preference.PreferenceManager;
 import android.text.format.Formatter;
 import android.util.Log;
 
@@ -35,14 +34,11 @@ import org.lineageos.updater.R;
 import org.lineageos.updater.UpdaterReceiver;
 import org.lineageos.updater.UpdatesActivity;
 import org.lineageos.updater.misc.BuildInfoUtils;
-import org.lineageos.updater.misc.Constants;
-import org.lineageos.updater.misc.FileUtils;
 import org.lineageos.updater.misc.StringGenerator;
 import org.lineageos.updater.misc.Utils;
 import org.lineageos.updater.model.UpdateInfo;
 import org.lineageos.updater.model.UpdateStatus;
 
-import java.io.File;
 import java.io.IOException;
 import java.text.DateFormat;
 import java.text.NumberFormat;
@@ -186,36 +182,18 @@ public class UpdaterService extends Service {
                         return START_STICKY;
                     }
                 } else {
-                    boolean deleteUpdate = PreferenceManager.getDefaultSharedPreferences(this)
-                            .getBoolean(Constants.PREF_AUTO_DELETE_UPDATES, false);
-                    if (deleteUpdate) {
-                        // Renaming the file is enough to have it deleted automatically
-                        File uncrytpFile = new File(
-                                update.getFile().getAbsolutePath() + Constants.UNCRYPT_FILE_EXT);
-                        update.getFile().renameTo(uncrytpFile);
-                        installPackage(uncrytpFile);
-                    } else if (Utils.isEncrypted(this, update.getFile())) {
-                        // uncrypt rewrites the file so that it can be read without mounting
-                        // the filesystem, so create a copy of it.
-                        File uncrytpFile = new File(
-                                update.getFile().getAbsolutePath() + Constants.UNCRYPT_FILE_EXT);
-                        FileUtils.prepareForUncrypt(this, update.getFile(), uncrytpFile,
-                                new Runnable() {
-                                    @Override
-                                    public void run() {
-                                        installPackage(uncrytpFile);
-                                    }
-                                });
-                    } else {
-                        installPackage(update.getFile());
-                    }
+                    UpdateInstaller installer = new UpdateInstaller(this, mUpdaterController);
+                    installer.install(downloadId);
                 }
             } catch (IOException e) {
                 Log.e(TAG, "Could not install update", e);
                 // TODO: user facing message
             }
         } else if (ACTION_INSTALL_STOP.equals(intent.getAction())) {
-            if (ABUpdateInstaller.isInstallingUpdate(this)) {
+            if (UpdateInstaller.isInstalling()) {
+                UpdateInstaller installer = new UpdateInstaller(this, mUpdaterController);
+                installer.cancel();
+            } else if (ABUpdateInstaller.isInstallingUpdate(this)) {
                 ABUpdateInstaller installer = new ABUpdateInstaller(this, mUpdaterController);
                 installer.reconnect();
                 installer.cancel();
@@ -224,15 +202,6 @@ public class UpdaterService extends Service {
         return START_NOT_STICKY;
     }
 
-    private void installPackage(File update) {
-        try {
-            android.os.RecoverySystem.installPackage(this, update);
-        } catch (IOException e) {
-            // TODO: show error message
-            Log.e(TAG, "Could not install update", e);
-        }
-    }
-
     public Controller getUpdaterController() {
         return mUpdaterController;
     }
@@ -352,7 +321,9 @@ public class UpdaterService extends Service {
                 mNotificationBuilder.mActions.clear();
                 mNotificationBuilder.setProgress(0, 0, false);
                 mNotificationStyle.setSummaryText(null);
-                String text = getString(R.string.installing_update);
+                String text = UpdateInstaller.isInstalling() ?
+                        getString(R.string.dialog_prepare_zip_message) :
+                        getString(R.string.installing_update);
                 mNotificationStyle.bigText(text);
                 mNotificationBuilder.setTicker(text);
                 mNotificationBuilder.setOngoing(true);
@@ -419,7 +390,8 @@ public class UpdaterService extends Service {
         mNotificationBuilder.setProgress(100, progress, false);
         String percent = NumberFormat.getPercentInstance().format(progress / 100.f);
         mNotificationStyle.setSummaryText(percent);
-        mNotificationStyle.bigText(
+        boolean notAB = UpdateInstaller.isInstalling();
+        mNotificationStyle.bigText(notAB ? getString(R.string.dialog_prepare_zip_message) :
                 update.getFinalizing() ?
                         getString(R.string.finalizing_package) :
                         getString(R.string.preparing_ota_first_boot));
diff --git a/src/org/lineageos/updater/misc/FileUtils.java b/src/org/lineageos/updater/misc/FileUtils.java
index 02f6bd6e..fab50e6e 100644
--- a/src/org/lineageos/updater/misc/FileUtils.java
+++ b/src/org/lineageos/updater/misc/FileUtils.java
@@ -15,16 +15,7 @@
  */
 package org.lineageos.updater.misc;
 
-import android.app.NotificationManager;
-import android.app.ProgressDialog;
-import android.content.Context;
-import android.content.DialogInterface;
-import android.os.AsyncTask;
-import android.support.v7.app.NotificationCompat;
 import android.util.Log;
-import android.view.WindowManager;
-
-import org.lineageos.updater.R;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -104,79 +95,4 @@ public class FileUtils {
     public static void copyFile(File sourceFile, File destFile) throws IOException {
         copyFile(sourceFile, destFile, null);
     }
-
-    public static void prepareForUncrypt(Context context, File updateFile, File uncryptFile,
-            Runnable callback) {
-
-        final int NOTIFICATION_ID = 12;
-
-        new AsyncTask<Void, String, Boolean>() {
-
-            private ProgressDialog mProgressDialog;
-            private boolean mCancelled;
-            private ProgressCallBack mProgressCallBack;
-
-            @Override
-            protected void onPreExecute() {
-                super.onPreExecute();
-                Log.d(TAG, "Preparing update");
-                mProgressDialog = new ProgressDialog(context);
-                mProgressDialog.setTitle(R.string.app_name);
-                mProgressDialog.setMessage(context.getString(R.string.dialog_prepare_zip_message));
-                mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
-                mProgressDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
-                mProgressDialog.setCancelable(true);
-                mProgressDialog.setProgressNumberFormat(null);
-                mProgressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
-                    @Override
-                    public void onCancel(DialogInterface dialog) {
-                        cancel(true);
-                    }
-                });
-                mProgressDialog.setCanceledOnTouchOutside(false);
-                mProgressCallBack = new ProgressCallBack() {
-                    @Override
-                    public void update(int progress) {
-                        mProgressDialog.setProgress(progress);
-                    }
-                };
-                mProgressDialog.show();
-            }
-
-            @Override
-            protected Boolean doInBackground(Void... voids) {
-                try {
-                    copyFile(updateFile, uncryptFile, mProgressCallBack);
-                } catch (IOException e) {
-                    Log.e(TAG, "Error while copying the file", e);
-                }
-                return !mCancelled;
-            }
-
-            @Override
-            protected void onCancelled() {
-                mCancelled = true;
-                uncryptFile.delete();
-            }
-
-            @Override
-            protected void onPostExecute(Boolean success) {
-                if (!success || mCancelled) {
-                    Log.e(TAG, "Could not prepare the update, cancelled=" + mCancelled);
-                    uncryptFile.delete();
-                    NotificationManager nm = (NotificationManager) context.getSystemService(
-                            Context.NOTIFICATION_SERVICE);
-                    NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
-                    builder.setSmallIcon(R.drawable.ic_system_update);
-                    builder.setContentTitle(
-                            context.getString(R.string.notification_prepare_zip_error_title));
-                    final String notificationTag = updateFile.getAbsolutePath();
-                    nm.notify(notificationTag, NOTIFICATION_ID, builder.build());
-                } else {
-                    callback.run();
-                }
-                mProgressDialog.dismiss();
-            }
-        }.execute();
-    }
 }