diff --git a/gcd.py b/gcd.py
index a8eec38..cf715e3 100644
--- a/gcd.py
+++ b/gcd.py
@@ -43,7 +43,7 @@ def add_to_cksum(payload):
     global running_cksum
     for c in payload:
         running_cksum += c
-        running_cksum &= 0xff
+    running_cksum &= 0xff
 
 def get_tlv_comment(ttype):
     if ttype in TLV_TYPES: