#!/usr/bin/env python3
import sys

desp = 0x2000
numBytes = 0x2000
firstByte = desp + 0x200
lastByte = desp + numBytes - 1
checksum1 = desp + 0x270
checksum2 = desp + 0x271

def calc_checksum(buffer):
    total = 0
    for i in range(firstByte, lastByte + 1):
        if i not in (checksum1, checksum2):
            total += buffer[i]
    total += 3328
    buffer[checksum1] = total % 256
    buffer[checksum2] = (total >> 8) % 256

if len(sys.argv) != 3:
    print("Uso: python3 revert_2934.py save_in.srm save_out.srm")
    sys.exit(1)

infile = sys.argv[1]
outfile = sys.argv[2]

with open(infile, "rb") as f:
    buf = bytearray(f.read())

# revertir el posible flag del armario
buf[0x02934] = 0xEE  # valor original

calc_checksum(buf)

with open(outfile, "wb") as f:
    f.write(buf)

print("Hecho:", outfile)