diff --git a/ethosu/vela/tflite_writer.py b/ethosu/vela/tflite_writer.py
index 687b887..8cabb0a 100644
--- a/ethosu/vela/tflite_writer.py
+++ b/ethosu/vela/tflite_writer.py
@@ -25,6 +25,7 @@
 from .nn_graph import PassPlacement
 from .operation import Op
 from .tensor import MemType
+from .tensor import TensorPurpose
 from .tflite import Buffer
 from .tflite import Metadata
 from .tflite import Model
@@ -37,6 +38,7 @@
 from .tflite_mapping import BuiltinOperator
 from .tflite_mapping import datatype_inv_map
 
+
 # ugh, the python flatbuffer interface is missing a method to add in file identifier. patching it in here:
 
 tflite_version = 3
@@ -345,7 +347,7 @@
 
         all_tensors = [tens for nm, idx, tens in sorted((tens.name, idx, tens) for idx, tens in enumerate(tensor_set))]
 
-        scratch_tensors = [tens for tens in all_tensors if tens.name.endswith("scratch")]
+        scratch_tensors = [tens for tens in all_tensors if tens.purpose is TensorPurpose.Scratch]
 
         if len(scratch_tensors) == 0:
             scratch_tensor = None