diff options
| -rw-r--r-- | scripts/signrom.py | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/scripts/signrom.py b/scripts/signrom.py index f9c35cc..6c8b9bf 100644 --- a/scripts/signrom.py +++ b/scripts/signrom.py @@ -18,10 +18,29 @@ fin = open(sys.argv[1], 'rb') fout = open(sys.argv[2], 'wb') fin.seek(2) -size = ord(fin.read(1)) * 512 - 1 - +size_byte = ord(fin.read(1)) fin.seek(0) -data = fin.read(size) + +if size_byte == 0: + # If the caller left the size field blank then we will fill it in, + # also rounding the whole input to a multiple of 512 bytes. + data = fin.read() + # +1 because we need a byte to store the checksum. + size = len(data) + 1 + # Round up to next multiple of 512. + size += 511 + size -= size % 512 + if size >= 65536: + sys.exit("%s: option ROM size too large" % sys.argv[1]) + # size-1 because a final byte is added below to store the checksum. + data = data.ljust(size-1, '\0') + data = data[:2] + chr(size/512) + data[3:] +else: + # Otherwise the input file specifies the size so use it. + # -1 because we overwrite the last byte of the file with the checksum. + size = size_byte * 512 - 1 + data = fin.read(size) + fout.write(data) checksum = 0 |