Archipelago » qemu

#

# Option ROM signing utility

#

# Authors:

#  Jan Kiszka <jan.kiszka@siemens.com>

#

# This work is licensed under the terms of the GNU GPL, version 2 or later.

# See the COPYING file in the top-level directory.

import sys

import struct

if len(sys.argv) < 3:

    print('usage: signrom.py input output')

    sys.exit(1)

fin = open(sys.argv[1], 'rb')

fout = open(sys.argv[2], 'wb')

fin.seek(2)

size = ord(fin.read(1)) * 512 - 1

fin.seek(0)

data = fin.read(size)

fout.write(data)

checksum = 0

for b in data:

    # catch Python 2 vs. 3 differences

    if isinstance(b, int):

        checksum += b

    else:

        checksum += ord(b)

checksum = (256 - checksum) % 256

# Python 3 no longer allows chr(checksum)

fout.write(struct.pack('B', checksum))

fin.close()

fout.close()