diff --git a/Patch.py b/Patch.py
index 94646c70..2c8adae3 100644
--- a/Patch.py
+++ b/Patch.py
@@ -2,8 +2,11 @@ import bsdiff4
 import yaml
 import os
 import lzma
+import hashlib
+import logging
 
 import Utils
+from Rom import JAP10HASH
 
 base_rom_bytes = None
 
@@ -15,6 +18,12 @@ def get_base_rom_bytes() -> bytes:
             options = Utils.parse_yaml(f.read())
         file_name = options["general_options"]["rom_file"]
         base_rom_bytes = load_bytes(file_name)
+
+        basemd5 = hashlib.md5()
+        basemd5.update(base_rom_bytes)
+        if JAP10HASH != basemd5.hexdigest():
+            logging.getLogger('').warning('Supplied Base Rom does not match known MD5 for JAP(1.0) release.'
+                                          ' Will try to patch anyway.')
     return base_rom_bytes