diff --git a/android_app/app/src/main/java/com/health/openscale/core/bluetooth/BluetoothBeurerBF700_800.java b/android_app/app/src/main/java/com/health/openscale/core/bluetooth/BluetoothBeurerBF700_800.java
index ca80f9ec..7ad6c73c 100644
--- a/android_app/app/src/main/java/com/health/openscale/core/bluetooth/BluetoothBeurerBF700_800.java
+++ b/android_app/app/src/main/java/com/health/openscale/core/bluetooth/BluetoothBeurerBF700_800.java
@@ -30,7 +30,6 @@ import com.health.openscale.core.utils.Converters;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.nio.ByteBuffer;
 import java.text.ParseException;
 import java.util.Arrays;
 import java.util.Collections;
@@ -523,7 +522,7 @@ public class BluetoothBeurerBF700_800 extends BluetoothCommunication {
             throw new ParseException("Parse scala data: unexpected length", 0);
         }
 
-        long timestamp = ByteBuffer.wrap(data, 0, 4).getInt() * 1000L;
+        long timestamp = Converters.fromUnsignedInt32Be(data, 0) * 1000;
         float weight = getKiloGram(data, 4);
         int impedance = Converters.fromUnsignedInt16Be(data, 6);
         float fat = getPercent(data, 8);
@@ -553,10 +552,11 @@ public class BluetoothBeurerBF700_800 extends BluetoothCommunication {
     private void updateDateTimeBeurer() {
         // Update date/time of the scale
         long unixTime = System.currentTimeMillis() / 1000L;
-        byte[] unixTimeBytes = ByteBuffer.allocate(Long.SIZE / 8).putLong(unixTime).array();
+        byte[] unixTimeBytes = Converters.toUnsignedInt32Be(unixTime);
         Log.d(TAG, "Write new Date/Time:" + unixTime + " " + byteInHex(unixTimeBytes));
 
-        writeBytes(new byte[]{(byte) getAlternativeStartByte(9), unixTimeBytes[4], unixTimeBytes[5], unixTimeBytes[6], unixTimeBytes[7]});
+        writeBytes(new byte[]{(byte) getAlternativeStartByte(9),
+                unixTimeBytes[0], unixTimeBytes[1], unixTimeBytes[2], unixTimeBytes[3]});
     }
 
     private void setUnitCommand() {
diff --git a/android_app/app/src/main/java/com/health/openscale/core/utils/Converters.java b/android_app/app/src/main/java/com/health/openscale/core/utils/Converters.java
index 7213a802..836d3158 100644
--- a/android_app/app/src/main/java/com/health/openscale/core/utils/Converters.java
+++ b/android_app/app/src/main/java/com/health/openscale/core/utils/Converters.java
@@ -129,4 +129,21 @@ public class Converters {
         value += data[offset + 1] & 0xFF;
         return value;
     }
+
+    public static long fromUnsignedInt32Be(byte[] data, int offset) {
+        long value = (long) (data[offset] & 0xFF) << 24;
+        value += (data[offset + 1] & 0xFF) << 16;
+        value += (data[offset + 2] & 0xFF) << 8;
+        value += data[offset + 3] & 0xFF;
+        return value;
+    }
+
+    public static byte[] toUnsignedInt32Be(long value) {
+        byte[] data = new byte[4];
+        data[0] = (byte) ((value >> 24) & 0xFF);
+        data[1] = (byte) ((value >> 16) & 0xFF);
+        data[2] = (byte) ((value >> 8) & 0xFF);
+        data[3] = (byte) (value & 0xFF);
+        return data;
+    }
 }
diff --git a/android_app/app/src/test/java/com/health/openscale/ConvertersTest.java b/android_app/app/src/test/java/com/health/openscale/ConvertersTest.java
index 22e666e6..ad344232 100644
--- a/android_app/app/src/test/java/com/health/openscale/ConvertersTest.java
+++ b/android_app/app/src/test/java/com/health/openscale/ConvertersTest.java
@@ -23,6 +23,7 @@ import org.junit.Test;
 import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertTrue;
+import static org.junit.Assert.assertArrayEquals;
 
 public class ConvertersTest {
 
@@ -88,4 +89,21 @@ public class ConvertersTest {
         assertEquals(0xfc10, Converters.fromUnsignedInt16Be(data, 2));
         assertEquals(0x107f, Converters.fromUnsignedInt16Be(data, 3));
     }
+
+    @Test
+    public void unsignedInt32Converters() throws Exception {
+        byte[] data = new byte[]{(byte) 0xf1, (byte) 0xf2, (byte) 0xf3, (byte) 0x7f, (byte) 0x7e};
+        assertEquals(0xf1f2f37fL, Converters.fromUnsignedInt32Be(data, 0));
+        assertEquals(0xf2f37f7eL, Converters.fromUnsignedInt32Be(data, 1));
+
+        data = new byte[]{(byte) 0x80, (byte) 0x00, (byte) 0x01, (byte) 0xff, (byte) 0x00};
+        assertEquals(0x800001ffL, Converters.fromUnsignedInt32Be(data, 0));
+        assertEquals(0x1ff00L, Converters.fromUnsignedInt32Be(data, 1));
+
+        data = new byte[]{(byte) 0xff, (byte) 0xfe, (byte) 0xfd, (byte) 0xfc};
+        assertArrayEquals(data, Converters.toUnsignedInt32Be(0xfffefdfcL));
+        assertEquals(0xffffffffL,
+                Converters.fromUnsignedInt32Be(
+                        Converters.toUnsignedInt32Be(0xffffffffL), 0));
+    }
 }