diff --git a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/SensorUtils.java b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/SensorUtils.java
index 7424b727c..e52103f23 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/SensorUtils.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/SensorUtils.java
@@ -86,10 +86,8 @@ public class SensorUtils {
     
     for (int i = 0; i < 8; i++) {
       if ((crc & 0x1) != 0x0) {
-		// we have to do the OxFF mask because the right shift is
-		// supposed to shift in a 0
-    	// as crc gets implicitly casted to a
-		// signed int by >> it may be filled with 1s
+	// Using a 0xFF bit assures that 0-bits are introduced during the shift operation. 
+	// Otherwise, implicit casts to signed int could shift in 1-bits if the signed bit is 1.
         crc = (byte) (((crc & 0xFF) >> 1) ^ 0x8C);
       } else {
         crc = (byte) ((crc & 0xFF) >> 1);
diff --git a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ZephyrMessageParser.java b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ZephyrMessageParser.java
index 1b86e6822..7d55632e3 100644
--- a/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ZephyrMessageParser.java
+++ b/MyTracks/src/com/google/android/apps/mytracks/services/sensors/ZephyrMessageParser.java
@@ -27,9 +27,9 @@ import com.google.android.apps.mytracks.content.Sensor;
  */
 public class ZephyrMessageParser implements MessageParser {
 
-	public static final int ZEPHYR_HXM_BYTE_STX = 0;
-	public static final int ZEPHYR_HXM_BYTE_CRC = 58;
-	public static final int ZEPHYR_HXM_BYTE_ETX = 59;
+    public static final int ZEPHYR_HXM_BYTE_STX = 0;
+    public static final int ZEPHYR_HXM_BYTE_CRC = 58;
+    public static final int ZEPHYR_HXM_BYTE_ETX = 59;
 	
   @Override
   public Sensor.SensorDataSet parseBuffer(byte[] buffer) {
@@ -63,13 +63,13 @@ public class ZephyrMessageParser implements MessageParser {
 
   @Override
   public boolean isValid(byte[] buffer) {
-	if (buffer.length > ZEPHYR_HXM_BYTE_ETX) {
-	  // Check STX (Start of Text), ETX (End of Text) and CRC Checksum
-	  return buffer[ZEPHYR_HXM_BYTE_STX] == 0x02
-	  && buffer[ZEPHYR_HXM_BYTE_ETX] == 0x03
-	  && SensorUtils.getCrc8(buffer, 3, 55) == buffer[ZEPHYR_HXM_BYTE_CRC];
-	} else
-		return false;
+    if (buffer.length > ZEPHYR_HXM_BYTE_ETX) {
+      // Check STX (Start of Text), ETX (End of Text) and CRC Checksum
+      return buffer[ZEPHYR_HXM_BYTE_STX] == 0x02
+      && buffer[ZEPHYR_HXM_BYTE_ETX] == 0x03
+      && SensorUtils.getCrc8(buffer, 3, 55) == buffer[ZEPHYR_HXM_BYTE_CRC];
+    } else
+      return false;
   }
 
   @Override