diff --git a/src/finn/custom_op/fpgadataflow/hlscustomop.py b/src/finn/custom_op/fpgadataflow/hlscustomop.py
index b202e95a28a26de3dabc098c2030bafcf840d164..c5041acd46a63880160f7726946e1c609642710d 100644
--- a/src/finn/custom_op/fpgadataflow/hlscustomop.py
+++ b/src/finn/custom_op/fpgadataflow/hlscustomop.py
@@ -138,6 +138,7 @@ class HLSCustomOp(CustomOp):
         intf_names["m_axis"] = [("out_" + sname, self.get_outstream_width_padded())]
         intf_names["aximm"] = []
         intf_names["axilite"] = []
+        intf_names["ap_none"] = []
         return intf_names
 
     def get_verilog_top_filename(self):