diff --git a/extern/UnifiedNlp b/extern/UnifiedNlp
index ea09d3ff..c161d40f 160000
--- a/extern/UnifiedNlp
+++ b/extern/UnifiedNlp
@@ -1 +1 @@
-Subproject commit ea09d3ff063c8ad32db492343bd640c3ac53bf2c
+Subproject commit c161d40f1bfe1c185b67d8120e4d51339d31e280
diff --git a/play-services-core/src/main/AndroidManifest.xml b/play-services-core/src/main/AndroidManifest.xml
index 254ee9b8..f79dc5cf 100644
--- a/play-services-core/src/main/AndroidManifest.xml
+++ b/play-services-core/src/main/AndroidManifest.xml
@@ -383,8 +383,8 @@
 
         <!-- Chimera spoof -->
         <provider
-            android:authorities="com.google.android.gms.chimera"
             android:name="org.microg.gms.ChimeraSpoofProvider"
+            android:authorities="com.google.android.gms.chimera"
             android:exported="true"/>
 
         <!-- microG custom UI -->
@@ -426,6 +426,11 @@
             android:label="@string/service_name_mcs"
             android:theme="@style/Theme.AppCompat.Settings"/>
 
+        <activity
+            android:name="org.microg.gms.ui.SafetyNetFragment$AsActivity"
+            android:label="@string/service_name_snet"
+            android:theme="@style/Theme.AppCompat.Settings"/>
+
         <activity
             android:name="org.microg.gms.ui.SelfCheckFragment$AsActivity"
             android:label="@string/self_check_title"
diff --git a/play-services-core/src/main/java/org/microg/gms/snet/Attestation.java b/play-services-core/src/main/java/org/microg/gms/snet/Attestation.java
index 73e63b54..916cd456 100644
--- a/play-services-core/src/main/java/org/microg/gms/snet/Attestation.java
+++ b/play-services-core/src/main/java/org/microg/gms/snet/Attestation.java
@@ -53,7 +53,6 @@ import okio.ByteString;
 
 public class Attestation {
     private static final String TAG = "GmsSafetyNetAttest";
-    private static final String ATTEST_URL = "https://www.googleapis.com/androidcheck/v1/attestations/attest?alt=PROTO&key=AIzaSyDqVnJBjE5ymo--oBJt3On7HQx9xNm1RHA";
 
     private Context context;
     private String packageName;
@@ -144,14 +143,11 @@ public class Attestation {
         if (payload == null) {
             throw new IllegalStateException("missing payload");
         }
-        if (droidGaurdResult == null || droidGaurdResult.isEmpty()) {
-            throw new IllegalStateException("missing droidGuard");
-        }
         return attest(new AttestRequest(ByteString.of(payload), droidGaurdResult)).result;
     }
 
     private AttestResponse attest(AttestRequest request) throws IOException {
-        HttpURLConnection connection = (HttpURLConnection) new URL(ATTEST_URL).openConnection();
+        HttpURLConnection connection = (HttpURLConnection) new URL(SafetyNetPrefs.get(context).getServiceUrl()).openConnection();
         connection.setRequestMethod("POST");
         connection.setDoInput(true);
         connection.setDoOutput(true);
@@ -180,9 +176,13 @@ public class Attestation {
         }
 
         InputStream is = connection.getInputStream();
-        AttestResponse response = new Wire().parseFrom(new GZIPInputStream(is), AttestResponse.class);
-        is.close();
-        return response;
+        byte[] bytes = Utils.readStreamToEnd(new GZIPInputStream(is));
+        try {
+            return new Wire().parseFrom(bytes, AttestResponse.class);
+        } catch (IOException e) {
+            Log.d(TAG, Base64.encodeToString(bytes, 0));
+            throw e;
+        }
     }
 
 
diff --git a/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetClientServiceImpl.java b/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetClientServiceImpl.java
index e5ed62e1..cdbe6bf2 100644
--- a/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetClientServiceImpl.java
+++ b/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetClientServiceImpl.java
@@ -56,6 +56,12 @@ public class SafetyNetClientServiceImpl extends ISafetyNetService.Stub {
             return;
         }
 
+        if (!SafetyNetPrefs.get(context).isEnabled()) {
+            Log.d(TAG, "ignoring SafetyNet request, it's disabled");
+            callbacks.onAttestationData(Status.CANCELED, null);
+            return;
+        }
+
         new Thread(new Runnable() {
             @Override
             public void run() {
@@ -65,10 +71,11 @@ public class SafetyNetClientServiceImpl extends ISafetyNetService.Stub {
                         RemoteDroidGuardConnector conn = new RemoteDroidGuardConnector(context);
                         Bundle bundle = new Bundle();
                         bundle.putString("contentBinding", attestation.getPayloadHashBase64());
-                        RemoteDroidGuardConnector.Result dg = conn.guard("attest", Long.toString(LastCheckinInfo.read(context).androidId),
-                                bundle, Utils.getDeviceIdentifier(context).meid, Utils.getPhoneInfo(context).imsi);
-                        if (dg != null && dg.getStatusCode() == 0 && dg.getResult() != null) {
-                            attestation.setDroidGaurdResult(Base64.encodeToString(dg.getResult(), Base64.NO_WRAP + Base64.NO_PADDING + Base64.URL_SAFE));
+                        RemoteDroidGuardConnector.Result dg = conn.guard("attest", Long.toString(LastCheckinInfo.read(context).androidId), bundle);
+                        if (!SafetyNetPrefs.get(context).isOfficial() || dg != null && dg.getStatusCode() == 0 && dg.getResult() != null) {
+                            if (dg != null && dg.getStatusCode() == 0 && dg.getResult() != null) {
+                                attestation.setDroidGaurdResult(Base64.encodeToString(dg.getResult(), Base64.NO_WRAP + Base64.NO_PADDING + Base64.URL_SAFE));
+                            }
                             AttestationData data = new AttestationData(attestation.attest());
                             callbacks.onAttestationData(Status.SUCCESS, data);
                         } else {
diff --git a/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetPrefs.java b/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetPrefs.java
new file mode 100644
index 00000000..4eafa82e
--- /dev/null
+++ b/play-services-core/src/main/java/org/microg/gms/snet/SafetyNetPrefs.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2017 microG Project Team
+ *
+ * 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.microg.gms.snet;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
+
+public class SafetyNetPrefs implements SharedPreferences.OnSharedPreferenceChangeListener {
+    private static final String OFFICIAL_ATTEST_URL = "https://www.googleapis.com/androidcheck/v1/attestations/attest?alt=PROTO&key=AIzaSyDqVnJBjE5ymo--oBJt3On7HQx9xNm1RHA";
+
+    public static final String PREF_SNET_DISABLED = "snet_disabled";
+    public static final String PREF_SNET_OFFICIAL = "snet_official";
+    public static final String PREF_SNET_THIRD_PARTY = "snet_third_party";
+    public static final String PREF_SNET_CUSTOM_URL = "snet_custom_url";
+
+    private static SafetyNetPrefs INSTANCE;
+
+    public static SafetyNetPrefs get(Context context) {
+        if (INSTANCE == null) {
+            if (context == null) return new SafetyNetPrefs(null);
+            INSTANCE = new SafetyNetPrefs(context.getApplicationContext());
+        }
+        return INSTANCE;
+    }
+
+    private boolean disabled;
+    private boolean official;
+    private boolean thirdParty;
+    private String customUrl;
+
+    private SharedPreferences defaultPreferences;
+
+    private SafetyNetPrefs(Context context) {
+        if (context != null) {
+            defaultPreferences = PreferenceManager.getDefaultSharedPreferences(context);
+            defaultPreferences.registerOnSharedPreferenceChangeListener(this);
+            update();
+        }
+    }
+
+    public void update() {
+        disabled = defaultPreferences.getBoolean(PREF_SNET_DISABLED, true);
+        official = defaultPreferences.getBoolean(PREF_SNET_OFFICIAL, false);
+        thirdParty = defaultPreferences.getBoolean(PREF_SNET_THIRD_PARTY, false);
+        customUrl = defaultPreferences.getString(PREF_SNET_CUSTOM_URL, null);
+    }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String s) {
+        update();
+    }
+
+    public boolean isEnabled() {
+        return !disabled && (official || thirdParty);
+    }
+
+    public boolean isOfficial() {
+        return official;
+    }
+
+    public String getServiceUrl() {
+        if (official) return OFFICIAL_ATTEST_URL;
+        return customUrl;
+    }
+}
diff --git a/play-services-core/src/main/java/org/microg/gms/ui/SafetyNetFragment.java b/play-services-core/src/main/java/org/microg/gms/ui/SafetyNetFragment.java
new file mode 100644
index 00000000..089dffaa
--- /dev/null
+++ b/play-services-core/src/main/java/org/microg/gms/ui/SafetyNetFragment.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2017 microG Project Team
+ *
+ * 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.microg.gms.ui;
+
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
+import android.support.v7.preference.Preference;
+
+import com.google.android.gms.R;
+
+import org.microg.tools.ui.AbstractSettingsActivity;
+import org.microg.tools.ui.RadioButtonPreference;
+import org.microg.tools.ui.ResourceSettingsFragment;
+
+import static org.microg.gms.snet.SafetyNetPrefs.PREF_SNET_DISABLED;
+import static org.microg.gms.snet.SafetyNetPrefs.PREF_SNET_OFFICIAL;
+import static org.microg.gms.snet.SafetyNetPrefs.PREF_SNET_THIRD_PARTY;
+
+public class SafetyNetFragment extends ResourceSettingsFragment {
+
+    public SafetyNetFragment() {
+        preferencesResource = R.xml.preferences_snet;
+    }
+
+    private RadioButtonPreference radioDisabled;
+    private RadioButtonPreference radioOfficial;
+    private RadioButtonPreference radioThirdParty;
+
+    @Override
+    public void onCreatePreferencesFix(@Nullable Bundle savedInstanceState, String rootKey) {
+        super.onCreatePreferencesFix(savedInstanceState, rootKey);
+
+        radioDisabled = (RadioButtonPreference) findPreference(PREF_SNET_DISABLED);
+        radioOfficial = (RadioButtonPreference) findPreference(PREF_SNET_OFFICIAL);
+        radioThirdParty = (RadioButtonPreference) findPreference(PREF_SNET_THIRD_PARTY);
+    }
+
+    @Override
+    public boolean onPreferenceTreeClick(Preference preference) {
+        if (preference == radioDisabled) {
+            radioDisabled.setChecked(true);
+            radioOfficial.setChecked(false);
+            radioThirdParty.setChecked(false);
+            return true;
+        } else if (preference == radioOfficial) {
+            radioDisabled.setChecked(false);
+            radioOfficial.setChecked(true);
+            radioThirdParty.setChecked(false);
+            return true;
+        } else if (preference == radioThirdParty) {
+            radioDisabled.setChecked(false);
+            radioOfficial.setChecked(false);
+            radioThirdParty.setChecked(true);
+            return true;
+        }
+        return super.onPreferenceTreeClick(preference);
+    }
+
+    public static class AsActivity extends AbstractSettingsActivity {
+        public AsActivity() {
+            showHomeAsUp = true;
+        }
+
+        @Override
+        protected Fragment getFragment() {
+            return new SafetyNetFragment();
+        }
+    }
+}
\ No newline at end of file
diff --git a/play-services-core/src/main/java/org/microg/gms/ui/SettingsActivity.java b/play-services-core/src/main/java/org/microg/gms/ui/SettingsActivity.java
index 44bd623f..da68a337 100644
--- a/play-services-core/src/main/java/org/microg/gms/ui/SettingsActivity.java
+++ b/play-services-core/src/main/java/org/microg/gms/ui/SettingsActivity.java
@@ -19,12 +19,12 @@ package org.microg.gms.ui;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
-import android.support.v7.preference.PreferenceManager;
 
 import com.google.android.gms.R;
 
 import org.microg.gms.gcm.GcmDatabase;
 import org.microg.gms.gcm.GcmPrefs;
+import org.microg.gms.snet.SafetyNetPrefs;
 import org.microg.tools.ui.AbstractDashboardActivity;
 import org.microg.tools.ui.ResourceSettingsFragment;
 
@@ -45,6 +45,7 @@ public class SettingsActivity extends AbstractDashboardActivity {
 
         public static final String PREF_ABOUT = "pref_about";
         public static final String PREF_GCM = "pref_gcm";
+        public static final String PREF_SNET = "pref_snet";
 
         public FragmentImpl() {
             preferencesResource = R.xml.preferences_start;
@@ -53,16 +54,26 @@ public class SettingsActivity extends AbstractDashboardActivity {
         @Override
         public void onCreatePreferencesFix(@Nullable Bundle savedInstanceState, String rootKey) {
             super.onCreatePreferencesFix(savedInstanceState, rootKey);
-            PreferenceManager prefs = getPreferenceManager();
-            prefs.findPreference(PREF_ABOUT).setSummary(getString(R.string.about_version_str, AboutFragment.getSelfVersion(getContext())));
+            updateDetails();
+        }
+
+        @Override
+        public void onResume() {
+            super.onResume();
+            updateDetails();
+        }
+
+        private void updateDetails() {
+            findPreference(PREF_ABOUT).setSummary(getString(R.string.about_version_str, AboutFragment.getSelfVersion(getContext())));
             if (GcmPrefs.get(getContext()).isGcmEnabled()) {
                 GcmDatabase database = new GcmDatabase(getContext());
                 int regCount = database.getRegistrationList().size();
                 database.close();
-                prefs.findPreference(PREF_GCM).setSummary(getString(R.string.v7_preference_on) + " / " + getContext().getString(R.string.gcm_registered_apps_counter, regCount));
+                findPreference(PREF_GCM).setSummary(getString(R.string.v7_preference_on) + " / " + getContext().getString(R.string.gcm_registered_apps_counter, regCount));
             } else {
-                prefs.findPreference(PREF_GCM).setSummary(R.string.v7_preference_off);
+                findPreference(PREF_GCM).setSummary(R.string.v7_preference_off);
             }
+            findPreference(PREF_SNET).setSummary(SafetyNetPrefs.get(getContext()).isEnabled() ? R.string.service_status_enabled : R.string.service_status_disabled);
         }
     }
 }
diff --git a/play-services-core/src/main/res/drawable/certificate.xml b/play-services-core/src/main/res/drawable/certificate.xml
new file mode 100644
index 00000000..6091e969
--- /dev/null
+++ b/play-services-core/src/main/res/drawable/certificate.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24"
+        android:viewportHeight="24">
+
+    <path
+        android:fillColor="#000000"
+        android:pathData="M4,3C2.89,3 2,3.89 2,5V15A2,2 0 0,0 4,17H12V22L15,19L18,22V17H20A2,2 0 0,0
+22,15V8L22,6V5A2,2 0 0,0
+20,3H16V3H4M12,5L15,7L18,5V8.5L21,10L18,11.5V15L15,13L12,15V11.5L9,10L12,8.5V5M4,5H9V7H4V5M4,9H7V11H4V9M4,13H9V15H4V13Z" />
+</vector>
\ No newline at end of file
diff --git a/play-services-core/src/main/res/values/strings.xml b/play-services-core/src/main/res/values/strings.xml
index d369cc4f..93eba842 100644
--- a/play-services-core/src/main/res/values/strings.xml
+++ b/play-services-core/src/main/res/values/strings.xml
@@ -55,6 +55,10 @@ This can take a couple of minutes."</string>
 
     <string name="service_name_checkin">Google device registration</string>
     <string name="service_name_mcs">Google Cloud Messaging</string>
+    <string name="service_name_snet">Google SafetyNet</string>
+
+    <string name="service_status_disabled">Disabled</string>
+    <string name="service_status_enabled">Enabled</string>
 
     <string name="pref_checkin_enable_summary">Registers your device to Google services and creates a unique device identifier. microG strips identifying bits other than your Google account name from registration data.</string>
     <string name="pref_gcm_enable_mcs_summary">Google Cloud Messaging is a push notification provider used by many third-party applications. To use it you must enable device registration.</string>
@@ -138,4 +142,20 @@ This can take a couple of minutes."</string>
     <string name="network_type_wifi">Wi-Fi</string>
     <string name="network_type_roaming">Roaming</string>
     <string name="network_type_other">Other networks</string>
+
+    <string name="snet_intro">Google SafetyNet is a device certification system, ensuring that the device is properly secured and compatible with Android CTS. Some applications use SafetyNet for security reasons or as a prerequisite for tamper-protection.\n\nmicroG GmsCore contains a free implementation of SafetyNet, but the official server requires SafetyNet requests to be signed using the proprietary DroidGuard system. A sandboxed version of DroidGuard is available as a separate “DroidGuard Helper” app.</string>
+
+    <string name="prefcat_configuration">Configuration</string>
+
+    <string name="pref_snet_status_disabled_title">Disabled</string>
+    <string name="pref_snet_status_disabled_summary">Completely disable SafetyNet</string>
+    <string name="pref_snet_status_official_title">Use official server</string>
+    <string name="pref_snet_status_official_summary">Requires an unrooted system, device registration enabled and microG DroidGuard Helper installed</string>
+    <string name="pref_snet_status_third_party_title">Use third-party server</string>
+    <string name="pref_snet_status_third_party_summary">Third-party servers might be able to reply to SafetyNet requests without DroidGuard signature</string>
+    <string name="pref_snet_custom_url_title">Custom server URL</string>
+    <string name="pref_snet_custom_url_summary">Full URL of the third-party server answering SafetyNet attestation requests</string>
+
+    <string name="prefcat_test">Test</string>
+    <string name="pref_snet_testdrive_title">Try SafetyNet attestation</string>
 </resources>
diff --git a/play-services-core/src/main/res/xml/preferences_snet.xml b/play-services-core/src/main/res/xml/preferences_snet.xml
new file mode 100644
index 00000000..46816e98
--- /dev/null
+++ b/play-services-core/src/main/res/xml/preferences_snet.xml
@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2017 microG Project Team
+  ~
+  ~ 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.
+  -->
+
+<PreferenceScreen
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <Preference
+        android:selectable="false"
+        android:summary="@string/snet_intro"/>
+    <PreferenceCategory android:title="@string/prefcat_configuration">
+        <org.microg.tools.ui.RadioButtonPreference
+            android:defaultValue="true"
+            android:key="snet_disabled"
+            android:summary="@string/pref_snet_status_disabled_summary"
+            android:title="@string/pref_snet_status_disabled_title"/>
+        <org.microg.tools.ui.RadioButtonPreference
+            android:checked="false"
+            android:key="snet_official"
+            android:summary="@string/pref_snet_status_official_summary"
+            android:title="@string/pref_snet_status_official_title"/>
+        <org.microg.tools.ui.RadioButtonPreference
+            android:checked="false"
+            android:key="snet_third_party"
+            android:summary="@string/pref_snet_status_third_party_summary"
+            android:title="@string/pref_snet_status_third_party_title"/>
+        <EditTextPreference
+            android:dependency="snet_third_party"
+            android:hint="https://example.com/server?key=123"
+            android:key="snet_custom_url"
+            android:summary="@string/pref_snet_custom_url_summary"
+            android:title="@string/pref_snet_custom_url_title"/>
+    </PreferenceCategory>
+    <PreferenceCategory android:title="@string/prefcat_test">
+        <Preference
+            android:enabled="false"
+            android:key="pref_snet_run_attest"
+            android:summary="Not yet available"
+            android:title="@string/pref_snet_testdrive_title"/>
+    </PreferenceCategory>
+</PreferenceScreen>
\ No newline at end of file
diff --git a/play-services-core/src/main/res/xml/preferences_start.xml b/play-services-core/src/main/res/xml/preferences_start.xml
index 72721933..f7dd98de 100644
--- a/play-services-core/src/main/res/xml/preferences_start.xml
+++ b/play-services-core/src/main/res/xml/preferences_start.xml
@@ -41,6 +41,14 @@
                 android:targetClass="org.microg.gms.ui.GcmFragment$AsActivity"
                 android:targetPackage="com.google.android.gms"/>
         </org.microg.tools.ui.TintIconPreference>
+        <org.microg.tools.ui.TintIconPreference
+            android:icon="@drawable/certificate"
+            android:key="pref_snet"
+            android:title="@string/service_name_snet">
+            <intent
+                android:targetClass="org.microg.gms.ui.SafetyNetFragment$AsActivity"
+                android:targetPackage="com.google.android.gms"/>
+        </org.microg.tools.ui.TintIconPreference>
         <org.microg.tools.ui.TintIconPreference
             android:icon="@drawable/location_marker"
             android:title="@string/nlp_settings_label">