diff --git a/src/finn/transformation/fpgadataflow/insert_iodma.py b/src/finn/transformation/fpgadataflow/insert_iodma.py
index 2a2e056f0c8db8dc1c5320be9c5788941083c07e..e4368edea717f7499481e9b1c6ac20f7d5bb5f58 100644
--- a/src/finn/transformation/fpgadataflow/insert_iodma.py
+++ b/src/finn/transformation/fpgadataflow/insert_iodma.py
@@ -59,6 +59,7 @@ class InsertIODMA(Transformation):
         fc_extw_nodes = list(
             filter(
                 lambda x: x.op_type == "StreamingFCLayer_Batch"
+                and get_by_name(x.attribute, "mem_mode") is not None
                 and get_by_name(x.attribute, "mem_mode").s.decode("UTF-8") == "external"
                 and model.find_producer(x.input[1]) is None,
                 all_nodes,