text: #!/usr/bin/env python
  ############################################################################
  #
  #   Copyright (c) 2012-2017 PX4 Development Team. All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #
  # 1. Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  # 2. Redistributions in binary form must reproduce the above copyright
  #    notice, this list of conditions and the following disclaimer in
  #    the documentation and/or other materials provided with the
  #    distribution.
  # 3. Neither the name PX4 nor the names of its contributors may be
  #    used to endorse or promote products derived from this software
  #    without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  # COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  # OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  #
  ############################################################################
  
  #
  # Serial firmware uploader for the PX4FMU bootloader
  #
  # The PX4 firmware file is a JSON-encoded Python object, containing
  # metadata fields and a zlib-compressed base64-encoded firmware image.
  #
  # The uploader uses the following fields from the firmware file:
  #
  # image
  #       The firmware that will be uploaded.
  # image_size
  #       The size of the firmware in bytes.
  # board_id
  #       The board for which the firmware is intended.
  # board_revision
  #       Currently only used for informational purposes.
  #
  
  # for python2.7 compatibility
  from __future__ import print_function
  
  import sys
  import argparse
  import binascii
  import serial
  import struct
  import json
  import zlib
  import base64
  import time
  import array
  import os
  
  from sys import platform as _platform
  
  # Detect python version
  if sys.version_info[0] < 3:
      runningPython3 = False
  else:
      runningPython3 = True
  
  # list of tuples (bootloader boardID, firmware boardID, boardname)
  # designating firmware builds compatible with multiple boardIDs
  compatible_IDs = [(33, 9, 'AUAVX2.1')]
  
  class firmware(object):
      '''Loads a firmware file'''
  
      desc = {}
      image = bytes()
      crctab = array.array('I', [
          0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
          0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
          0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
          0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
          0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
          0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
          0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
          0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
          0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
          0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
          0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
          0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
          0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
          0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
          0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
          0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
          0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
          0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
          0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
          0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
          0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
          0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
          0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
          0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
          0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
          0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
          0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
          0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
          0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
          0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
          0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
          0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d])
      crcpad = bytearray(b'\xff\xff\xff\xff')
  
      def __init__(self, path):
  
          # read the file
          f = open(path, "r")
          self.desc = json.load(f)
          f.close()
  
          self.image = bytearray(zlib.decompress(base64.b64decode(self.desc['image'])))
  
          # pad image to 4-byte length
          while ((len(self.image) % 4) != 0):
              self.image.append('\xff')
  
      def property(self, propname):
          return self.desc[propname]
  
      def __crc32(self, bytes, state):
          for byte in bytes:
              index = (state ^ byte) & 0xff
              state = self.crctab[index] ^ (state >> 8)
          return state
  
      def crc(self, padlen):
          state = self.__crc32(self.image, int(0))
          for i in range(len(self.image), (padlen - 1), 4):
              state = self.__crc32(self.crcpad, state)
          return state
  
  
  class uploader(object):
      '''Uploads a firmware file to the PX FMU bootloader'''
  
      # protocol bytes
      INSYNC          = b'\x12'
      EOC             = b'\x20'
  
      # reply bytes
      OK              = b'\x10'
      FAILED          = b'\x11'
      INVALID         = b'\x13'     # rev3+
      BAD_SILICON_REV = b'\x14'     # rev5+
  
      # command bytes
      NOP             = b'\x00'     # guaranteed to be discarded by the bootloader
      GET_SYNC        = b'\x21'
      GET_DEVICE      = b'\x22'
      CHIP_ERASE      = b'\x23'
      CHIP_VERIFY     = b'\x24'     # rev2 only
      PROG_MULTI      = b'\x27'
      READ_MULTI      = b'\x28'     # rev2 only
      GET_CRC         = b'\x29'     # rev3+
      GET_OTP         = b'\x2a'     # rev4+  , get a word from OTP area
      GET_SN          = b'\x2b'     # rev4+  , get a word from SN area
      GET_CHIP        = b'\x2c'     # rev5+  , get chip version
      SET_BOOT_DELAY  = b'\x2d'     # rev5+  , set boot delay
      GET_CHIP_DES    = b'\x2e'     # rev5+  , get chip description in ASCII
      MAX_DES_LENGTH  = 20
  
      REBOOT          = b'\x30'
      SET_BAUD        = b'\x33'     # set baud
  
      INFO_BL_REV     = b'\x01'        # bootloader protocol revision
      BL_REV_MIN      = 2              # minimum supported bootloader protocol
      BL_REV_MAX      = 5              # maximum supported bootloader protocol
      INFO_BOARD_ID   = b'\x02'        # board type
      INFO_BOARD_REV  = b'\x03'        # board revision
      INFO_FLASH_SIZE = b'\x04'        # max firmware size in bytes
  
      PROG_MULTI_MAX  = 252            # protocol max is 255, must be multiple of 4
      READ_MULTI_MAX  = 252            # protocol max is 255
  
      NSH_INIT        = bytearray(b'\x0d\x0d\x0d')
      NSH_REBOOT_BL   = b"reboot -b\n"
      NSH_REBOOT      = b"reboot\n"
      MAVLINK_REBOOT_ID1 = bytearray(b'\xfe\x21\x72\xff\x00\x4c\x00\x00\x40\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xf6\x00\x01\x00\x00\x53\x6b')
      MAVLINK_REBOOT_ID0 = bytearray(b'\xfe\x21\x45\xff\x00\x4c\x00\x00\x40\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xf6\x00\x00\x00\x00\xcc\x37')
  
      def __init__(self, portname, baudrate_bootloader, baudrate_flightstack, baudrate_bootloader_flash=None):
          # open the port, keep the default timeout short so we can poll quickly
          self.port = serial.Serial(portname, baudrate_bootloader, timeout=0.5)
          self.otp = b''
          self.sn = b''
          self.baudrate_bootloader = baudrate_bootloader
          if baudrate_bootloader_flash is not None:
              self.baudrate_bootloader_flash = baudrate_bootloader_flash
          else:
              self.baudrate_bootloader_flash = self.baudrate_bootloader
          self.baudrate_flightstack = baudrate_flightstack
          self.baudrate_flightstack_idx = -1
  
      def close(self):
          if self.port is not None:
              self.port.close()
  
      def open(self):
          timeout = time.time() + 0.2
  
          # Attempt to open the port while it exists and until timeout occurs
          while self.port is not None:
              portopen = True
              try:
                  portopen = self.port.is_open
              except AttributeError:
                  portopen = self.port.isOpen()
  
              if not portopen and time.time() < timeout:
                  try:
                      self.port.open()
                  except OSError:
                      # wait for the port to be ready
                      time.sleep(0.04)
                  except serial.SerialException:
                      # if open fails, try again later
                      time.sleep(0.04)
  
              else:
                  break
  
      def __send(self, c):
          # print("send " + binascii.hexlify(c))
          self.port.write(c)
  
      def __recv(self, count=1):
          c = self.port.read(count)
          if len(c) < 1:
              raise RuntimeError("timeout waiting for data (%u bytes)" % count)
          # print("recv " + binascii.hexlify(c))
          return c
  
      def __recv_int(self):
          raw = self.__recv(4)
          val = struct.unpack("<I", raw)
          return val[0]
  
      def __getSync(self):
          self.port.flush()
          c = bytes(self.__recv())
          if c != self.INSYNC:
              raise RuntimeError("unexpected %s instead of INSYNC" % c)
          c = self.__recv()
          if c == self.INVALID:
              raise RuntimeError("bootloader reports INVALID OPERATION")
          if c == self.FAILED:
              raise RuntimeError("bootloader reports OPERATION FAILED")
          if c != self.OK:
              raise RuntimeError("unexpected response 0x%x instead of OK" % ord(c))
  
      # attempt to get back into sync with the bootloader
      def __sync(self):
          # send a stream of ignored bytes longer than the longest possible conversation
          # that we might still have in progress
          # self.__send(uploader.NOP * (uploader.PROG_MULTI_MAX + 2))
          self.port.flushInput()
          self.__send(uploader.GET_SYNC +
                      uploader.EOC)
          self.__getSync()
  
      def __trySync(self):
          try:
              self.port.flush()
              if (self.__recv() != self.INSYNC):
                  # print("unexpected 0x%x instead of INSYNC" % ord(c))
                  return False
              c = self.__recv()
              if (c == self.BAD_SILICON_REV):
                  raise NotImplementedError()
              if (c != self.OK):
                  # print("unexpected 0x%x instead of OK" % ord(c))
                  return False
              return True
  
          except NotImplementedError:
              raise RuntimeError("Programing not supported for this version of silicon!\n"
                                 "See https://pixhawk.org/help/errata")
          except RuntimeError:
              # timeout, no response yet
              return False
  
      # send the GET_DEVICE command and wait for an info parameter
      def __getInfo(self, param):
          self.__send(uploader.GET_DEVICE + param + uploader.EOC)
          value = self.__recv_int()
          self.__getSync()
          return value
  
      # send the GET_OTP command and wait for an info parameter
      def __getOTP(self, param):
          t = struct.pack("I", param)  # int param as 32bit ( 4 byte ) char array.
          self.__send(uploader.GET_OTP + t + uploader.EOC)
          value = self.__recv(4)
          self.__getSync()
          return value
  
      # send the GET_SN command and wait for an info parameter
      def __getSN(self, param):
          t = struct.pack("I", param)  # int param as 32bit ( 4 byte ) char array.
          self.__send(uploader.GET_SN + t + uploader.EOC)
          value = self.__recv(4)
          self.__getSync()
          return value
  
      # send the GET_CHIP command
      def __getCHIP(self):
          self.__send(uploader.GET_CHIP + uploader.EOC)
          value = self.__recv_int()
          self.__getSync()
          return value
  
      # send the GET_CHIP command
      def __getCHIPDes(self):
          self.__send(uploader.GET_CHIP_DES + uploader.EOC)
          length = self.__recv_int()
          value = self.__recv(length)
          self.__getSync()
          peices = value.split(",")
          return peices
  
      def __drawProgressBar(self, label, progress, maxVal):
          if maxVal < progress:
              progress = maxVal
  
          percent = (float(progress) / float(maxVal)) * 100.0
  
          sys.stdout.write("\r%s: [%-20s] %.1f%%" % (label, '='*int(percent/5.0), percent))
          sys.stdout.flush()
  
      # send the CHIP_ERASE command and wait for the bootloader to become ready
      def __erase(self, label):
          print("\n", end='')
          self.__send(uploader.CHIP_ERASE +
                      uploader.EOC)
  
          # erase is very slow, give it 30s
          deadline = time.time() + 30.0
          while time.time() < deadline:
  
              # Draw progress bar (erase usually takes about 9 seconds to complete)
              estimatedTimeRemaining = deadline-time.time()
              if estimatedTimeRemaining >= 9.0:
                  self.__drawProgressBar(label, 30.0-estimatedTimeRemaining, 9.0)
              else:
                  self.__drawProgressBar(label, 10.0, 10.0)
                  sys.stdout.write(" (timeout: %d seconds) " % int(deadline-time.time()))
                  sys.stdout.flush()
  
              if self.__trySync():
                  self.__drawProgressBar(label, 10.0, 10.0)
                  return
  
          raise RuntimeError("timed out waiting for erase")
  
      # send a PROG_MULTI command to write a collection of bytes
      def __program_multi(self, data):
  
          if runningPython3:
              length = len(data).to_bytes(1, byteorder='big')
          else:
              length = chr(len(data))
  
          self.__send(uploader.PROG_MULTI)
          self.__send(length)
          self.__send(data)
          self.__send(uploader.EOC)
          self.__getSync()
  
      # verify multiple bytes in flash
      def __verify_multi(self, data):
  
          if runningPython3:
              length = len(data).to_bytes(1, byteorder='big')
          else:
              length = chr(len(data))
  
          self.__send(uploader.READ_MULTI)
          self.__send(length)
          self.__send(uploader.EOC)
          self.port.flush()
          programmed = self.__recv(len(data))
          if programmed != data:
              print("got    " + binascii.hexlify(programmed))
              print("expect " + binascii.hexlify(data))
              return False
          self.__getSync()
          return True
  
      # send the reboot command
      def __reboot(self):
          self.__send(uploader.REBOOT +
                      uploader.EOC)
          self.port.flush()
  
          # v3+ can report failure if the first word flash fails
          if self.bl_rev >= 3:
              self.__getSync()
  
      # split a sequence into a list of size-constrained pieces
      def __split_len(self, seq, length):
          return [seq[i:i+length] for i in range(0, len(seq), length)]
  
      # upload code
      def __program(self, label, fw):
          print("\n", end='')
          code = fw.image
          groups = self.__split_len(code, uploader.PROG_MULTI_MAX)
  
          uploadProgress = 0
          for bytes in groups:
              self.__program_multi(bytes)
  
              # Print upload progress (throttled, so it does not delay upload progress)
              uploadProgress += 1
              if uploadProgress % 256 == 0:
                  self.__drawProgressBar(label, uploadProgress, len(groups))
          self.__drawProgressBar(label, 100, 100)
  
      # verify code
      def __verify_v2(self, label, fw):
          print("\n", end='')
          self.__send(uploader.CHIP_VERIFY +
                      uploader.EOC)
          self.__getSync()
          code = fw.image
          groups = self.__split_len(code, uploader.READ_MULTI_MAX)
          verifyProgress = 0
          for bytes in groups:
              verifyProgress += 1
              if verifyProgress % 256 == 0:
                  self.__drawProgressBar(label, verifyProgress, len(groups))
              if (not self.__verify_multi(bytes)):
                  raise RuntimeError("Verification failed")
          self.__drawProgressBar(label, 100, 100)
  
      def __verify_v3(self, label, fw):
          print("\n", end='')
          self.__drawProgressBar(label, 1, 100)
          expect_crc = fw.crc(self.fw_maxsize)
          self.__send(uploader.GET_CRC +
                      uploader.EOC)
          report_crc = self.__recv_int()
          self.__getSync()
          if report_crc != expect_crc:
              print("Expected 0x%x" % expect_crc)
              print("Got      0x%x" % report_crc)
              raise RuntimeError("Program CRC failed")
          self.__drawProgressBar(label, 100, 100)
  
      def __set_boot_delay(self, boot_delay):
          self.__send(uploader.SET_BOOT_DELAY +
                      struct.pack("b", boot_delay) +
                      uploader.EOC)
          self.__getSync()
  
      def __setbaud(self, baud):
          self.__send(uploader.SET_BAUD +
                      struct.pack("I", baud) +
                      uploader.EOC)
          self.__getSync()
  
      # get basic data about the board
      def identify(self):
          # make sure we are in sync before starting
          self.__sync()
  
          # get the bootloader protocol ID first
          self.bl_rev = self.__getInfo(uploader.INFO_BL_REV)
          if (self.bl_rev < uploader.BL_REV_MIN) or (self.bl_rev > uploader.BL_REV_MAX):
              print("Unsupported bootloader protocol %d" % uploader.INFO_BL_REV)
              raise RuntimeError("Bootloader protocol mismatch")
  
          self.board_type = self.__getInfo(uploader.INFO_BOARD_ID)
          self.board_rev = self.__getInfo(uploader.INFO_BOARD_REV)
          self.fw_maxsize = self.__getInfo(uploader.INFO_FLASH_SIZE)
  
      # upload the firmware
      def upload(self, fw, force=False, boot_delay=None):
          # Make sure we are doing the right thing
          if self.board_type != fw.property('board_id'):
              # ID mismatch: check compatibility
              incomp = True
              for entry in compatible_IDs:
                  if (entry[0] == self.board_type) and (entry[1] == fw.property('board_id')):
                       msg = "Target %s (board_id: %d) is compatible with firmware for board_id=%u)" % (
                           entry[2], self.board_type, fw.property('board_id'))
                       print("INFO: %s" % msg)
                       incomp = False
                       break
              if incomp:                        
                  msg = "Firmware not suitable for this board (board_type=%u board_id=%u)" % (
                      self.board_type, fw.property('board_id'))
                  print("WARNING: %s" % msg)
                  
                  if force:
                      print("FORCED WRITE, FLASHING ANYWAY!")
                  else:
                      raise IOError(msg)
          if self.fw_maxsize < fw.property('image_size'):
              raise RuntimeError("Firmware image is too large for this board")
  
          # OTP added in v4:
          if self.bl_rev > 3:
              for byte in range(0, 32*6, 4):
                  x = self.__getOTP(byte)
                  self.otp = self.otp + x
                  print(binascii.hexlify(x).decode('Latin-1') + ' ', end='')
              # see src/modules/systemlib/otp.h in px4 code:
              self.otp_id = self.otp[0:4]
              self.otp_idtype = self.otp[4:5]
              self.otp_vid = self.otp[8:4:-1]
              self.otp_pid = self.otp[12:8:-1]
              self.otp_coa = self.otp[32:160]
              # show user:
              try:
                  print("type: " + self.otp_id.decode('Latin-1'))
                  print("idtype: " + binascii.b2a_qp(self.otp_idtype).decode('Latin-1'))
                  print("vid: " + binascii.hexlify(self.otp_vid).decode('Latin-1'))
                  print("pid: " + binascii.hexlify(self.otp_pid).decode('Latin-1'))
                  print("coa: " + binascii.b2a_base64(self.otp_coa).decode('Latin-1'))
                  print("sn: ", end='')
                  for byte in range(0, 12, 4):
                      x = self.__getSN(byte)
                      x = x[::-1]  # reverse the bytes
                      self.sn = self.sn + x
                      print(binascii.hexlify(x).decode('Latin-1'), end='')  # show user
                  print('')
                  print("chip: %08x" % self.__getCHIP())
                  if (self.bl_rev >= 5):
                      des = self.__getCHIPDes()
                      if (len(des) == 2):
                          print("family: %s" % des[0])
                          print("revision: %s" % des[1])
                          print("flash %d" % self.fw_maxsize)
              except Exception:
                  # ignore bad character encodings
                  pass
  
          if self.baudrate_bootloader_flash != self.baudrate_bootloader:
              print("Setting baudrate to %u" % self.baudrate_bootloader_flash)
              self.__setbaud(self.baudrate_bootloader_flash)
              self.port.baudrate = self.baudrate_bootloader_flash
              self.__sync()
  
          self.__erase("Erase  ")
          self.__program("Program", fw)
  
          if self.bl_rev == 2:
              self.__verify_v2("Verify ", fw)
          else:
              self.__verify_v3("Verify ", fw)
  
          if boot_delay is not None:
              self.__set_boot_delay(boot_delay)
  
          print("\nRebooting.\n")
          self.__reboot()
          self.port.close()
  
      def __next_baud_flightstack(self):
          if self.baudrate_flightstack_idx + 1 >= len(self.baudrate_flightstack):
              return False
          try:
              self.port.baudrate = self.baudrate_flightstack[self.baudrate_flightstack_idx + 1]
              self.baudrate_flightstack_idx = self.baudrate_flightstack_idx + 1
          except serial.SerialException:
              # Sometimes _configure_port fails
              time.sleep(0.04)
  
          return True
  
      def send_reboot(self):
          if (not self.__next_baud_flightstack()):
              return False
  
          print("Attempting reboot on %s with baudrate=%d..." % (self.port.port, self.port.baudrate), file=sys.stderr)
          print("If the board does not respond, unplug and re-plug the USB connector.", file=sys.stderr)
  
          try:
              # try MAVLINK command first
              self.port.flush()
              self.__send(uploader.MAVLINK_REBOOT_ID1)
              self.__send(uploader.MAVLINK_REBOOT_ID0)
              # then try reboot via NSH
              self.__send(uploader.NSH_INIT)
              self.__send(uploader.NSH_REBOOT_BL)
              self.__send(uploader.NSH_INIT)
              self.__send(uploader.NSH_REBOOT)
              self.port.flush()
              self.port.baudrate = self.baudrate_bootloader
          except:
              try:
                  self.port.flush()
                  self.port.baudrate = self.baudrate_bootloader
              except Exception:
                  pass
  
          return True
  
  
  def main():
  
      # Parse commandline arguments
      parser = argparse.ArgumentParser(description="Firmware uploader for the PX autopilot system.")
      parser.add_argument('--port', action="store", required=True, help="Comma-separated list of serial port(s) to which the FMU may be attached")
      parser.add_argument('--baud-bootloader', action="store", type=int, default=115200, help="Baud rate of the serial port (default is 115200) when communicating with bootloader, only required for true serial ports.")
      parser.add_argument('--baud-bootloader-flash', action="store", type=int, default=None, help="Attempt to negotiate this baudrate with bootloader for flashing.")
      parser.add_argument('--baud-flightstack', action="store", default="57600", help="Comma-separated list of baud rate of the serial port (default is 57600) when communicating with flight stack (Mavlink or NSH), only required for true serial ports.")
      parser.add_argument('--force', action='store_true', default=False, help='Override board type check and continue loading')
      parser.add_argument('--boot-delay', type=int, default=None, help='minimum boot delay to store in flash')
      parser.add_argument('firmware', action="store", help="Firmware file to be uploaded")
      args = parser.parse_args()
  
      # warn people about ModemManager which interferes badly with Pixhawk
      if os.path.exists("/usr/sbin/ModemManager"):
          print("==========================================================================================================")
          print("WARNING: You should uninstall ModemManager as it conflicts with any non-modem serial device (like Pixhawk)")
          print("==========================================================================================================")
  
      # Load the firmware file
      fw = firmware(args.firmware)
      print("Loaded firmware for %x,%x, size: %d bytes, waiting for the bootloader..." % (fw.property('board_id'), fw.property('board_revision'), fw.property('image_size')))
      print("If the board does not respond within 1-2 seconds, unplug and re-plug the USB connector.")
  
      # Spin waiting for a device to show up
      try:
          while True:
              portlist = []
              patterns = args.port.split(",")
              # on unix-like platforms use glob to support wildcard ports. This allows
              # the use of /dev/serial/by-id/usb-3D_Robotics on Linux, which prevents the upload from
              # causing modem hangups etc
              if "linux" in _platform or "darwin" in _platform:
                  import glob
                  for pattern in patterns:
                      portlist += glob.glob(pattern)
              else:
                  portlist = patterns
  
              baud_flightstack = [int(x) for x in args.baud_flightstack.split(',')]
  
              for port in portlist:
  
                  # print("Trying %s" % port)
  
                  # create an uploader attached to the port
                  try:
                      if "linux" in _platform:
                          # Linux, don't open Mac OS and Win ports
                          if "COM" not in port and "tty.usb" not in port:
                              up = uploader(port, args.baud_bootloader, baud_flightstack, args.baud_bootloader_flash)
                      elif "darwin" in _platform:
                          # OS X, don't open Windows and Linux ports
                          if "COM" not in port and "ACM" not in port:
                              up = uploader(port, args.baud_bootloader, baud_flightstack, args.baud_bootloader_flash)
                      elif "win" in _platform:
                          # Windows, don't open POSIX ports
                          if "/" not in port:
                              up = uploader(port, args.baud_bootloader, baud_flightstack, args.baud_bootloader_flash)
                  except Exception:
                      # open failed, rate-limit our attempts
                      time.sleep(0.05)
  
                      # and loop to the next port
                      continue
  
                  found_bootloader = False
                  while (True):
                      up.open()
  
                      # port is open, try talking to it
                      try:
                          # identify the bootloader
                          up.identify()
                          found_bootloader = True
                          print("Found board %x,%x bootloader rev %x on %s" % (up.board_type, up.board_rev, up.bl_rev, port))
                          break
  
                      except Exception:
  
                          if not up.send_reboot():
                              break
  
                          # wait for the reboot, without we might run into Serial I/O Error 5
                          time.sleep(0.25)
  
                          # always close the port
                          up.close()
  
                          # wait for the close, without we might run into Serial I/O Error 6
                          time.sleep(0.3)
  
                  if not found_bootloader:
                      # Go to the next port
                      continue
  
                  try:
                      # ok, we have a bootloader, try flashing it
                      up.upload(fw, force=args.force, boot_delay=args.boot_delay)
  
                  except RuntimeError as ex:
                      # print the error
                      print("\nERROR: %s" % ex.args)
  
                  except IOError:
                      up.close()
                      continue
  
                  finally:
                      # always close the port
                      up.close()
  
                  # we could loop here if we wanted to wait for more boards...
                  sys.exit(0)
  
              # Delay retries to < 20 Hz to prevent spin-lock from hogging the CPU
              time.sleep(0.05)
  
      # CTRL+C aborts the upload/spin-lock by interrupt mechanics
      except KeyboardInterrupt:
          print("\n Upload aborted by user.")
          sys.exit(0)
  
  if __name__ == '__main__':
      main()
  
  # vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
  