diff --git a/test/functional/test_framework/blocktools.py b/test/functional/test_framework/blocktools.py
index 7c455ea52f2..c6ebf77deb8 100644
--- a/test/functional/test_framework/blocktools.py
+++ b/test/functional/test_framework/blocktools.py
@@ -35,7 +35,7 @@ from .script import (
     CScript,
     CScriptNum,
     CScriptOp,
-    OP_1,
+    OP_0,
     OP_RETURN,
     OP_TRUE,
 )
@@ -128,8 +128,8 @@ def add_witness_commitment(block, nonce=0):
 def script_BIP34_coinbase_height(height):
     if height <= 16:
         res = CScriptOp.encode_op_n(height)
-        # Append dummy to increase scriptSig size above 2 (see bad-cb-length consensus rule)
-        return CScript([res, OP_1])
+        # Append dummy to increase scriptSig size to 2 (see bad-cb-length consensus rule)
+        return CScript([res, OP_0])
     return CScript([CScriptNum(height)])