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oot/fixbaserom.py
Dragorn421 8e57f3bca3
Improve fixbaserom.py (#987)
Set bytes past ROM's end to `0xFF`.
Recognize the infamous ZeldaEdit-edited rom.
2021-11-01 14:21:05 -04:00

96 lines
3 KiB
Python

from os import path
import sys
import struct
import hashlib
def get_str_hash(byte_array):
return str(hashlib.md5(byte_array).hexdigest())
# If the baserom exists and is correct, we don't need to change anything
if path.exists("baserom.z64"):
with open("baserom.z64", mode="rb") as file:
fileContent = bytearray(file.read())
if get_str_hash(fileContent) == "f0b7f35375f9cc8ca1b2d59d78e35405":
print("Found valid baserom - exiting early")
sys.exit(0)
# Determine if we have a ROM file
romFileExtensions = ["z64", "n64", "v64"]
def find_baserom_original():
for romFileExtLower in romFileExtensions:
for romFileExt in (romFileExtLower, romFileExtLower.upper()):
romFileNameCandidate = "baserom_original." + romFileExt
if path.exists(romFileNameCandidate):
return romFileNameCandidate
return None
romFileName = find_baserom_original()
if romFileName is None:
print("Error: Could not find baserom_original.z64/baserom_original.n64/baserom_original.v64.")
sys.exit(1)
# Read in the original ROM
print("File '" + romFileName + "' found.")
with open(romFileName, mode="rb") as file:
fileContent = bytearray(file.read())
# Strip the overdump
print("Stripping overdump...")
fileContent = fileContent[0:0x3600000]
fileContentLen = len(fileContent)
# Check if ROM needs to be byte/word swapped
# Little-endian
if fileContent[0] == 0x40:
# Word Swap ROM
print("ROM needs to be word swapped...")
words = str(int(fileContentLen/4))
little_byte_format = "<" + words + "I"
big_byte_format = ">" + words + "I"
tmp = struct.unpack_from(little_byte_format, fileContent, 0)
struct.pack_into(big_byte_format, fileContent, 0, *tmp)
print("Word swapping done.")
# Byte-swapped
elif fileContent[0] == 0x37:
# Byte Swap ROM
print("ROM needs to be byte swapped...")
halfwords = str(int(fileContentLen/2))
little_byte_format = "<" + halfwords + "H"
big_byte_format = ">" + halfwords + "H"
tmp = struct.unpack_from(little_byte_format, fileContent, 0)
struct.pack_into(big_byte_format, fileContent, 0, *tmp)
print("Byte swapping done.")
# Patch the header
print("Patching header...")
fileContent[0x3E] = 0x50
for i in range(0x35CF000, len(fileContent)):
fileContent[i] = 0xFF
# Check to see if the ROM is a "vanilla" Debug ROM
str_hash = get_str_hash(bytearray(fileContent))
if str_hash != "f0b7f35375f9cc8ca1b2d59d78e35405":
print("Error: Expected a hash of f0b7f35375f9cc8ca1b2d59d78e35405 but got " + str_hash + ". " +
"The baserom has probably been tampered, find a new one")
if str_hash == "32fe2770c0f9b1a9cd2a4d449348c1cb":
print("The provided baserom is a rom which has been edited with ZeldaEdit and is not suitable for use with decomp. " +
"Find a new one.")
sys.exit(1)
# Write out our new ROM
print("Writing new ROM 'baserom.z64'.")
with open("baserom.z64", mode="wb") as file:
file.write(bytes(fileContent))
print("Done!")