Update 70mai firmware hash

sdbin.py

#!/usr/bin/env python3

from hashlib import md5
import sys
import codecs
import argparse
import logging

logging.basicConfig(level = logging.DEBUG)
log = logging.getLogger("update_hash")

SIGNATURE = codecs.decode(b"41495453010000000000000000000000", "hex")

def update_hash(rfd, wfd):
    
    fw = rfd.read()

    if fw[:0x10] != SIGNATURE:
        raise ValueError

    oldhash = fw[0x10:0x20]
    h = md5()
    h.update("VDRAC999".encode("ascii"))
    h.update(fw[0x20:])
    newhash = h.digest()
    log.info("Old hash = {}".format(codecs.encode(oldhash, "hex").decode("ascii")))
    log.info("New hash = {}".format(codecs.encode(newhash, "hex").decode("ascii")))

    wfd.write(SIGNATURE)
    wfd.write(newhash)
    wfd.write(fw[0x20:])

if __name__ == "__main__":
    p = argparse.ArgumentParser(description = "Update 70mai firmware hash")
    p.add_argument("infile", nargs = "?", type = argparse.FileType("rb"), default = sys.stdin.buffer)
    p.add_argument("outfile", nargs = "?", type = argparse.FileType("wb"), default = sys.stdout.buffer)
    args = p.parse_args()
    update_hash(args.infile, args.outfile)