import struct

file_path = 'rom.bin'

# Get the length of the file
with open(file_path, 'rb') as file:
    file_length = len(file.read())

# Subtract 1 from the file length
file_length -= 1

# Convert the file length to a 32-bit binary representation
binary_length = struct.pack('<I', file_length)

# Open the file in write mode and seek to the desired location (0x1A4)
with open(file_path, 'r+b') as file:
    file.seek(0x1A4)

    # Write the binary length to the file
    file.write(binary_length)