diff --git a/app/release/app-release-4.1.10.apk b/app/release/app-release-4.2.1l.apk
similarity index 63%
rename from app/release/app-release-4.1.10.apk
rename to app/release/app-release-4.2.1l.apk
index 90b6420..c9c5435 100644
Binary files a/app/release/app-release-4.1.10.apk and b/app/release/app-release-4.2.1l.apk differ
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 1954c1a..917802a 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -2,7 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:versionCode="128"
-    android:versionName="4.2.1k">
+    android:versionName="4.2.1l">
     <!-- android:allowBackup="false" -->
     <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
@@ -44,11 +44,12 @@
         <activity
             android:name=".MainActivity2"
             android:exported="false" />
-        <activity
+        <!--<activity
             android:name=".MlModelManager"
             android:exported="false"
             android:label="@string/title_activity_ml_model_manager"
             android:theme="@style/AppTheme" />
+            -->
         <activity android:name=".AuthenticateActivity" /> <!-- @android:style/Theme.Holo.Light" -->
         <activity android:name=".BLEScanActivity" />
         <activity android:name=".ExportDataActivity" /> <!-- android:usesCleartextTraffic="true" -->
diff --git a/app/src/main/java/uk/org/openseizuredetector/SdDataSourceBLE.java b/app/src/main/java/uk/org/openseizuredetector/SdDataSourceBLE.java
index a6c30ed..d5dca22 100644
--- a/app/src/main/java/uk/org/openseizuredetector/SdDataSourceBLE.java
+++ b/app/src/main/java/uk/org/openseizuredetector/SdDataSourceBLE.java
@@ -243,14 +243,16 @@ public class SdDataSourceBLE extends SdDataSource {
             } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
                 mConnectionState = STATE_DISCONNECTED;
                 mSdData.watchConnected = false;
-                Log.i(TAG, "onConnectionStateChange(): Disconnected from GATT server - reconnecting after delay...");
-                //bleDisconnect();  // Tidy up connections
+                Log.i(TAG, "onConnectionStateChange(): Disconnected from GATT server");
+                /**Log.i(TAG, "onConnectionStateChange(): Disconnected from GATT server - reconnecting after delay...");
+                bleDisconnect();  // Tidy up connections
                 // Wait 2 seconds to give the server chance to shutdown, then re-start it
                 mHandler.postDelayed(new Runnable() {
                     public void run() {
                         bleConnect();
                     }
                 }, 2000);
+                 */
             }
         }
 
@@ -403,7 +405,13 @@ public class SdDataSourceBLE extends SdDataSource {
                     //Log.d(TAG, "onDataReceived(): Heart rate format UINT8.");
                 }
                 final int heartRate = characteristic.getIntValue(format, 1);  // heart rate is second byte
-                mSdData.mHR = (double) heartRate;
+                // We normally use -1 for fault indication, but the BLE standard is for one byte for heart
+                // rate services, so we can't send -1, so treat either 0 or 255 as fault.
+                if (heartRate == 255 || heartRate == 0) {
+                    mSdData.mHR = -1;
+                } else {
+                    mSdData.mHR = (double) heartRate;
+                }
                 Log.d(TAG, String.format("onDataReceived(): CHAR_HEART_RATE_MEASUREMENT: %d", heartRate));
             }
             else if (characteristic.getUuid().toString().equals(CHAR_OSD_ACC_DATA)