Index: scripts/update_package_script/update_package.py
===================================================================
diff -u -r37ed1a7ad66212bf70875ea723fdae6576405ce8 -r52796f2db103cc8f253d00b7334b4f79c2d2cfd2
--- scripts/update_package_script/update_package.py	(.../update_package.py)	(revision 37ed1a7ad66212bf70875ea723fdae6576405ce8)
+++ scripts/update_package_script/update_package.py	(.../update_package.py)	(revision 52796f2db103cc8f253d00b7334b4f79c2d2cfd2)
@@ -35,6 +35,7 @@
     _MCS_DATA_TYPE_START_INDEX = 7
     _MCS_DATA_TYPE_END_INDEX = 9
     _MCS_UPDATE_DATA_START_INDEX = 9
+    _MCS_SUM_MODULO_256 = 256
 
 
     def __init__(self):
@@ -202,7 +203,8 @@
         """
         f = open(file_path, 'r')
         payload_bytes = bytes()
-        for line in f:
+        for line_number, line in enumerate(f, start=1):
+            summation = 0
             line = line.strip()
             # Read the line: e.g. :10000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00 -> :[Length][Address][Record Type][Data][Checksum]
             # 1. ":" is the start of the line
@@ -219,8 +221,24 @@
             if self._MCS_NUM_OF_BYTES_DEC != num_of_bytes: continue
             data_type = line[self._MCS_DATA_TYPE_START_INDEX:self._MCS_DATA_TYPE_END_INDEX]
             if self._MCS_DATA_DATA_TYPE_DEC != data_type: continue
-            update_data = line[self._MCS_UPDATE_DATA_START_INDEX:len(line) - self._MCS_LINE_CRC_LEN]
+            # Get the last two characters of the line as CRC
+            line_crc = line[len(line) - self._MCS_LINE_CRC_LEN:]
+            line_crc = line_crc[0] + line_crc[1]
+            line_crc = int(line_crc, 16)
+            data_line_without_crc = line[self._MCS_START_CODE_END_INDEX:len(line) - self._MCS_LINE_CRC_LEN]
 
+            for c in range(0, len(data_line_without_crc)):
+                # Loop through the line and sum all bytes (length, address, type, and data)
+                if c % 2 == 0: continue
+                int_value = data_line_without_crc[c - 1] + data_line_without_crc[c]
+                int_value = int(int_value, 16)
+                summation += int_value
+            # Get the 8-bit modulo. The CRC is the 2's complement
+            remainder = summation % self._MCS_SUM_MODULO_256
+            crc = self._MCS_SUM_MODULO_256 - remainder
+            if crc != line_crc: self._utilities.file_handle.write("Line Num: {}, Line: {}, Line CRC: {}, Calc CRC: {}\r".format(line_number, line, line_crc, crc)) # TODO if the CRC failed, we should fail the update
+
+            update_data = line[self._MCS_UPDATE_DATA_START_INDEX:len(line) - self._MCS_LINE_CRC_LEN]
             for b in range(0, len(update_data)):
                 # Loop through the list of the data extracted data every two characters are concatenated to become one byte of data
                 # For example: 00000000300020010000001430014004 -> 00 00 00 00 30 00 20 01 00 00 00 14 30 01 40 04
@@ -241,6 +259,7 @@
                 self._utilities.send_software_update_msg(target, payload_bytes, len(payload_bytes))
                 self._update_progress_status()
                 payload_bytes = bytes()
+        # Close the mcs file
         f.close()
 
     def _verify_stack_update(self):
@@ -318,7 +337,7 @@
         if len(list_of_update_files) == 0: exit(0)  # No update files to process
 
         #self._utilities.send_update_available_to_firmware_stacks() # TODO uncomment
-        #self._handle_broadcast_message_thread(start_thread=True)
+        self._handle_broadcast_message_thread(start_thread=True)
         time.sleep(1.5) # Wait a while or have a broadcast check
         for update_file in list_of_update_files:
            # Make sure the file is opened a binary or hex
@@ -329,4 +348,4 @@
                 self._verify_stack_update() # TODO skip if the timeout or another error
 
         # Done with update binary files, stop sending the broadcast message
-        #self._handle_broadcast_message_thread(start_thread=False)
+        self._handle_broadcast_message_thread(start_thread=False)