new_contents: #!/usr/bin/python3
  #
  # Copyright (C) 2019 Richard Hughes <richard@hughsie.com>
  #
  # SPDX-License-Identifier: LGPL-2.1+
  
  import sys
  import uuid
  import argparse
  import struct
  
  CAPSULE_FLAGS_PERSIST_ACROSS_RESET = 0x00010000
  CAPSULE_FLAGS_POPULATE_SYSTEM_TABLE = 0x00020000
  CAPSULE_FLAGS_INITIATE_RESET = 0x00040000
  
  def main(args):
  
      # parse GUID from command line
      try:
          guid = uuid.UUID(args.guid)
      except ValueError as e:
          print(e)
          return 1
      try:
          with open(args.bin, 'rb') as f:
              bin_data = f.read()
      except FileNotFoundError as e:
          print(e)
          return 1
  
      # check if already has header
      hdrsz = struct.calcsize('<16sIII')
      if len(bin_data) >= hdrsz:
          hdr = struct.unpack('<16sIII', bin_data[:hdrsz])
          imgsz = hdr[3]
          if imgsz == len(bin_data):
              print('Replacing existing CAPSULE_HEADER of:')
              guid_mixed = uuid.UUID(bytes_le=hdr[0])
              hdrsz_old = hdr[1]
              flags = hdr[2]
              print('GUID:      %s' % guid_mixed)
              print('HdrSz:     0x%04x' % hdrsz_old)
              print('Flags:     0x%04x' % flags)
              print('PayloadSz: 0x%04x' % imgsz)
              bin_data = bin_data[hdrsz_old:]
  
      # set header flags
      flags = CAPSULE_FLAGS_PERSIST_ACROSS_RESET | CAPSULE_FLAGS_INITIATE_RESET
      if hasattr(args, 'flags'):
          flags = int(args.flags, 16)
  
      # build update capsule header
      imgsz = hdrsz + len(bin_data)
      hdr = struct.pack('<16sIII', guid.bytes_le, hdrsz, flags, imgsz)
      with open(args.cap, 'wb') as f:
          f.write(hdr + bin_data)
      print('Wrote capsule %s' % args.cap)
      print('GUID:      %s' % guid)
      print('HdrSz:     0x%04x' % hdrsz)
      print('Flags:     0x%04x' % flags)
      print('PayloadSz: 0x%04x' % imgsz)
      return 0
  
  parser = argparse.ArgumentParser(description='Add capsule header on firmware')
  parser.add_argument('--guid', help='GUID of the device', required=True)
  parser.add_argument('--bin', help='Path to the .bin file', required=True)
  parser.add_argument('--cap', help='Output capsule file path', required=True)
  parser.add_argument('--flags', help='Flags, e.g. 0x40000')
  args = parser.parse_args()
  
  sys.exit(main(args))
  
subject: Add a simple script to add a capsule header