Index: scripts/update_package_script/utilities.py
===================================================================
diff -u -r167604cac199c133488d55eb0163e88eadd0e123 -r55bb8a403cfcdfcf213d608d42df63df4f29a305
--- scripts/update_package_script/utilities.py	(.../utilities.py)	(revision 167604cac199c133488d55eb0163e88eadd0e123)
+++ scripts/update_package_script/utilities.py	(.../utilities.py)	(revision 55bb8a403cfcdfcf213d608d42df63df4f29a305)
@@ -135,9 +135,9 @@
     _SEND_CMD_MAIL_BOX = 0x601
     _BROADCAST_UPDATE_MAIL_BOX = 0x606
 
-    _LEAHI_START_MESSAGE_BYTE = 0xA5
+    _LEAHI_MESSAGE_SYNC_BYTE = 0xA5
+    _LEAHI_MESSAGE_START_INDEX = 1
     _LEAHI_SEQ_1_BYTE = 0x1234
-    _LEAHI_SEQ_2_BYTE = 0x34
     _LEAHI_SIGNAL_TD_UPDATE_AVAILABLE = 0x00A6
     _LEAHI_SIGNAL_DD_UPDATE_AVAILABLE = 0x00A7
 
@@ -306,14 +306,15 @@
 
         @return none
         """
-        can_msg_bytes = self._convert_data_to_bytes('<B', self._LEAHI_START_MESSAGE_BYTE)
+        can_msg_bytes = self._convert_data_to_bytes('<B', self._LEAHI_MESSAGE_SYNC_BYTE)
         can_msg_bytes += self._convert_data_to_bytes('<H', self._LEAHI_SEQ_1_BYTE)
 
         for msg_id, mail_box in self._leahi_mail_boxes.items():
             # Loop through the Leahi mail boxes
             can_msg_bytes += self._convert_data_to_bytes('<H', msg_id)
             can_msg_bytes += self._convert_data_to_bytes('<B', 0) # Payload length is 0
-            crc_8 = self._get_crc8(can_msg_bytes[1:])
+            # The Leahi message CRC exclude the sync byte (0xA5)
+            crc_8 = self._get_crc8(can_msg_bytes[self._LEAHI_MESSAGE_START_INDEX:])
             can_msg_bytes += self._convert_data_to_bytes('<B', crc_8)
             can_msg_bytes += self._convert_data_to_bytes('<B', 0) # Padding the last byte to be an 8-byte frame
             mail_box_id = mail_box[self._STACK_SEND_UPDATE_MAIL_BOX]