diff --git a/tools/mkzip.py b/tools/mkzip.py
index c125a5a2..07f28577 100644
--- a/tools/mkzip.py
+++ b/tools/mkzip.py
@@ -5,6 +5,14 @@ import os
 import os.path
 import zipfile
 from shutil import copyfile
+import hashlib
+
+def md5(fname):
+    hash_md5 = hashlib.md5()
+    with open(fname, "rb") as f:
+        for chunk in iter(lambda: f.read(4096), b""):
+            hash_md5.update(chunk)
+    return hash_md5.hexdigest()
 
 if len(sys.argv) < 3:
     print('usage: mkzip <lstfile> <dstpath>')
@@ -21,9 +29,11 @@ with open(sys.argv[1], 'r') as f:
 
     for (fname, aname) in lst:
         path = os.path.join(sys.argv[2], aname)
-        if not os.path.exists(path):
+        old_md5 = md5(fname);
+        new_md5 = md5(path);
+        if not os.path.exists(path) or old_md5 != new_md5:
             os.makedirs(os.path.dirname(path), exist_ok=True)
             copyfile(fname, path)
             print("Copying: " + path)
         else:
-            print("Skipping: " + path)
+            print("Skipping: " + path + " - MD5: "+md5(fname))