diff --git a/patch.py b/patch.py
index 1c4c2ca..21d1c3e 100644
--- a/patch.py
+++ b/patch.py
@@ -18,7 +18,7 @@ def replace_key(old,new,data,name=''):
     old_chunks = [old[i:i+4] for i in range(0, len(old), 4)]
     new_chunks = [new[i:i+4] for i in range(0, len(new), 4)]
     data =  replace_chunks(old_chunks, new_chunks, data,name)
-    if os.environ['ARCH'] == '-arm64' and os.environ['LATEST_VERSION'] == '7.17.2':
+    if 'ARCH' in os.environ and  os.environ['ARCH'] == '-arm64' and os.environ['LATEST_VERSION'] == '7.17.2':
         old_bytes = old_chunks[4] + old_chunks[5] + old_chunks[2] + old_chunks[0] + old_chunks[1] + old_chunks[6] + old_chunks[7]
         new_bytes = new_chunks[4] + new_chunks[5] + new_chunks[2] + new_chunks[0] + new_chunks[1] + new_chunks[6] + new_chunks[7]
         if old_bytes in data: