Index: scripts/update_package_script/utilities.py
===================================================================
diff -u -rc9920f2e213be9ca443b157cf7107437cb231d89 -r5de5ce75fff6bc871400e2058eba7d0fb1a63cd4
--- scripts/update_package_script/utilities.py	(.../utilities.py)	(revision c9920f2e213be9ca443b157cf7107437cb231d89)
+++ scripts/update_package_script/utilities.py	(.../utilities.py)	(revision 5de5ce75fff6bc871400e2058eba7d0fb1a63cd4)
@@ -100,7 +100,7 @@
         cmd_combo = (target << self._SHIFT_BITS_BY_A_NIBBLE) | (cmd & 0xF)
         can_msg_bytes += self._convert_data_to_bytes('<B', cmd_combo)
         can_msg_bytes += self._convert_data_to_bytes('<H', 0) # This is the random value it is 0 for now
-        crc_32 = 0 #self._get_crc32(can_frame_bytes) # TODO what is wrong with this?
+        crc_32 = self._get_crc32(can_msg_bytes)
         can_msg_bytes += self._convert_data_to_bytes('<I', crc_32)
 
         self._send_can_message(self._SEND_CMD_MAIL_BOX, can_msg_bytes, self.SEND_MSG_ACK_STATUS_KEY_NAME,
@@ -110,27 +110,26 @@
         self._msg_ack_nack_status[self.SEND_MSG_ACK_STATUS_KEY_NAME] = CanCommStatus.CAN_COMM_SUCCESSFUL.value
         # TODO remove
 
-    def send_software_update_msg(self, target: int, data: list, signature_msg: bool = False):
+    def send_software_update_msg(self, target: int, data: list, update_payload_len: int, signature_msg: bool = False):
 
         mail_box = self._update_mail_boxes[target][0]
         time_out_s = self._update_mail_boxes[target][1]
         self._msg_id_count = self._msg_id_count + 1 if self._msg_id_count < 0xFF else 0
         self._total_msg_count += 1
         self._msg_sw_update_index += 1
-        crc_32 = 12340
         temp = bytes()
         can_msg_bytes = self._convert_data_to_bytes('<B', self._msg_id_count)
         can_msg_bytes += self._convert_data_to_bytes('<B', target)
         if signature_msg is False:
-            can_msg_bytes += self._convert_data_to_bytes('<H', self._msg_sw_update_index)
+            can_msg_bytes += self._convert_data_to_bytes('<H', update_payload_len)
         else:
             # struct does not accept 0xFFFF for 2 bytes pack
             can_msg_bytes += self._convert_data_to_bytes('<B', 0xFF)
             can_msg_bytes += self._convert_data_to_bytes('<B', 0xFF)
 
         for b in data: temp += self._convert_data_to_bytes('<B', b)
 
-        #crc_32 = self._get_crc32(can_msg_bytes + temp) # TODO figure out
+        crc_32 = self._get_crc32(can_msg_bytes + temp)
         can_msg_bytes += self._convert_data_to_bytes('<I', crc_32)
         can_msg_bytes += temp
         can_msg_bytes_len = len(can_msg_bytes)
@@ -161,8 +160,9 @@
         i = 0
 
         while length > 0:
-            #print(i, length, crc, data[i], data[i] ^ (crc >> cls._SHIFT_24_BITS), crc << cls._SHIFT_8_BITS_FOR_BYTE_SHIFT)
-            crc = (crc << cls._SHIFT_8_BITS_FOR_BYTE_SHIFT) ^ cls._CRC32_TABLE[data[i] ^ (crc >> cls._SHIFT_24_BITS)]
+            left = (crc << cls._SHIFT_8_BITS_FOR_BYTE_SHIFT) & 0xFFFFFFFF
+            right = (crc >> cls._SHIFT_24_BITS) & 0xFFFFFFFF
+            crc = left ^ cls._CRC32_TABLE[data[i] ^ right]
             i += 1
             length -= 1