eap1300_to_eap1300ext.py

#!/usr/bin/env python3

import sys

in_file = sys.argv[1]

lower = in_file.lower()
if 'eap1300ext' in lower or 'eap1300' not in lower:
    raise ValueError('This does not look like an EAP1300 firmware file name.')

out_file = in_file.replace('eap1300', 'eap1300ext').replace('EAP1300', 'EAP1300EXT')

with open(in_file, 'rb') as f:
    in_header = f.read(256)
    vendor_and_product = in_header[4:12]
    model_len = in_header[0x87]
    data_start = 0x88+model_len
    model = in_header[0x88:data_start]
    if model != b'EAP1300_A' or vendor_and_product != b'\0\0\1\1\0\0\0\x9d':
        raise ValueError('Header data does not look like it is for an EAP1300')

    out_header = in_header[0:0x87] + \
                 b'\x0cEAP1300EXT_A' + \
                 in_header[data_start:]

    with open(out_file, 'wb') as o:
        o.write(out_header)
        while True:
            block = f.read1()
            if not block: break
            o.write(block)