old_contents: #!/usr/bin/env python3
  
  from Crypto.Cipher import AES
  import binascii
  
  key = binascii.a2b_hex('d81c99faa2f8f6689cfdd2b5ebae63b4');  # Left over in RAM after boot
  iv = binascii.a2b_hex('7dc823ce45679e93c2b5681a53a9d051');   # Based on known-plaintext zero blocks
  
  infile = open('MINI3D Firmware V1.15 - Rocker Position Mode.bin', 'rb')
  outfile = open('plain.bin', 'wb')
  
  header = infile.read(8)
  
  while True:
      block = infile.read(512)
      if not block:
          break
      outfile.write(AES.new(key, AES.MODE_CBC, iv).decrypt(block))
  
new_contents: #!/usr/bin/env python3
  
  from Crypto.Cipher import AES
  import binascii
  
  key = binascii.a2b_hex('d81c99faa2f8f6689cfdd2b5ebae63b4');  # Left over in RAM after boot
  iv = binascii.a2b_hex('7dc823ce45679e93c2b5681a53a9d051');   # Based on known-plaintext zero blocks
  
  infile = open('MINI3D Firmware V1.15 - Rocker Position Mode.bin', 'rb')
  outfile = open('plain.bin', 'wb')
  
  header = infile.read(8)
  
  while True:
      block = infile.read(1024)
      if not block:
          break
      outfile.write(AES.new(key, AES.MODE_CBC, iv).decrypt(block))
  
subject: Fix block size