diff --git a/MyTracks/res/values/strings.xml b/MyTracks/res/values/strings.xml
index 44dace317..a8c569393 100644
--- a/MyTracks/res/values/strings.xml
+++ b/MyTracks/res/values/strings.xml
@@ -1221,18 +1221,18 @@ limitations under the License.
   </string>
   <string name="settings_display_track_color_dynamic_medium"
     translation_description="In the Display settings, under the 'Dynamic thresholds' configurations,
-      the option for configuring the medium speed percentage. It is the percentage from the average
-      speed to be considered as the medium speed. The track color mode will use different colors to
-      color a track depending on whether the speed is above, in, or below the medium speed range.">
-    Medium speed percentage
+      the option for configuring the percentage from the average speed to be considered as the
+      medium speed. The track color mode will use different colors to color a track depending on
+      whether the speed is above, in, or below the medium speed range.">
+    Medium percentage
   </string>
   <string name="settings_display_track_color_dynamic_medium_summary"
     translation_description="In the Display settings, under the 'Dynamic thresholds' configurations,
-      the summary for the 'Medium speed percentage' option explaining that it sets a percentage from
-      the average speed to be considered as the medium speed color. The track color mode will use
+      the summary for the 'Medium percentage' option explaining that it sets the percentage from
+      the average speed to be considered as the medium speed. The track color mode will use
       different colors to color a track depending on whether the speed is above, in, or below the
       medium speed range.">
-    Percentage from the average speed for the medium speed color.
+    Percentage from the average speed for the medium speed range.
   </string>
   <string name="settings_display_track_color_fixed"
     translation_description="In the Display settings, for the 'Track color mode' dropdown, the
@@ -1273,7 +1273,7 @@ limitations under the License.
   <string name="settings_display_track_color_summary"
     translation_description="In the Display settings, the summary for the 'Track color mode'
       dropdown explaining that it configures how colors are used to color a track based on speed.">
-    The way to color a track based on speed.
+    The way to color a track based on slow, medium, and high speed.
   </string>
   <string name="settings_not_while_recording"
     translation_description="In the Settings page, the summary for an option that is not available
diff --git a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntMessage.java b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntMessage.java
index 3f1b13529..b11c76da9 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntMessage.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntMessage.java
@@ -25,8 +25,8 @@ public class AntMessage {
 
   /** Build a short value from its constituent bytes */
   protected static short decodeShort(byte b0, byte b1) {
-    short value = b0;
-    value |= ((short) b1) << 8;
-    return value;
+    int value = b0 & 0xFF;
+    value |= (b1 & 0xFF) << 8;
+    return (short)value;
   }
 }
diff --git a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntSensorManager.java b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntSensorManager.java
index 7b5d896e3..0f565a3a1 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntSensorManager.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ant/AntSensorManager.java
@@ -92,7 +92,7 @@ public abstract class AntSensorManager extends SensorManager {
       String antAction = intent.getAction();
       Log.i(TAG, "enter data onReceive" + antAction);
 
-      if (antAction.equals(AntInterfaceIntent.ANT_RX_MESSAGE_ACTION)) {
+      if (antAction != null && antAction.equals(AntInterfaceIntent.ANT_RX_MESSAGE_ACTION)) {
         byte[] antMessage = intent.getByteArrayExtra(AntInterfaceIntent.ANT_MESSAGE);
         if (DEBUGGING) {
           Log.d(TAG, "Received RX message " + messageToString(antMessage));
@@ -185,22 +185,23 @@ public abstract class AntSensorManager extends SensorManager {
    * Cleans up the ANT+ receiver interface, by releasing the interface
    * and destroying it.
    */
-  private void cleanAntInterface()
-  {
+  private void cleanAntInterface() {
     Log.i(TAG, "Destroying AntSensorManager");
-    
-    if (antReceiver != null) {
-      try {
-        antReceiver.releaseInterface();
-      } catch (AntServiceNotConnectedException e) {
-        Log.i(TAG, "ANT service not connected", e);
-      } catch (AntInterfaceException e) {
-        Log.e(TAG, "failed to release ANT interface", e);
+
+    try {
+      if (antReceiver == null) {
+        Log.e(TAG, "no ANT receiver");
+        return;
       }
-  
+      antReceiver.releaseInterface();
       antReceiver.destroy();
-      
       antReceiver = null;
+    } catch (AntServiceNotConnectedException e) {
+      Log.i(TAG, "ANT service not connected", e);
+    } catch (AntInterfaceException e) {
+      Log.e(TAG, "failed to release ANT interface", e);
+    } catch (RuntimeException e) {
+      Log.e(TAG, "run-time exception when cleaning the ANT interface", e);
     }
   }
   
@@ -213,6 +214,11 @@ public abstract class AntSensorManager extends SensorManager {
     Log.d(TAG, "ANT service connected");
 
     try {
+      if (antReceiver == null) {
+        Log.e(TAG, "no ANT receiver");
+        return;
+      }
+      
       if (!antReceiver.claimInterface()) {
         Log.e(TAG, "failed to claim ANT interface");
         return;
@@ -300,6 +306,11 @@ public abstract class AntSensorManager extends SensorManager {
       byte radioFreq, byte proxSearch) {
 
     try {
+      if (antReceiver == null) {
+        Log.e(TAG, "no ANT receiver");
+        return false;        
+      }
+      
       // Assign as slave channel on selected network (0 = public, 1 = ANT+, 2 =
       // ANTFS)
       antReceiver.ANTAssignChannel(channelNumber, AntDefine.PARAMETER_RX_NOT_TX, networkNumber);