| # |
| # 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() |
