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#
# 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()
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