diff --git a/spacy/util.py b/spacy/util.py
index 47abddc43..9c7562e3f 100644
--- a/spacy/util.py
+++ b/spacy/util.py
@@ -437,7 +437,10 @@ def model_to_bytes(model):
     i = 0
     for layer in queue:
         if hasattr(layer, '_mem'):
-            weights.append(layer._mem.weights)
+            if layer._mem.weights.size:
+                weights.append(layer._mem.weights)
+            else:
+                weights.append(None)
             metas.append(tuple(layer._mem._offsets))
             dims.append(getattr(layer, '_dims', None))
             i += 1
@@ -458,9 +461,10 @@ def model_from_bytes(model, bytes_data):
     for layer in queue:
         if hasattr(layer, '_mem'):
             params = weights[i]
-            flat_mem = layer._mem._mem.ravel()
-            flat_params = params.ravel()
-            flat_mem[:flat_params.size] = flat_params
+            if params is not None:
+                flat_mem = layer._mem._mem.ravel()
+                flat_params = params.ravel()
+                flat_mem[:flat_params.size] = flat_params
             layer._mem._offsets.update(metas[i])
             if hasattr(layer, '_dims'):
                 layer._dims.update(dims[i])