diff --git a/unsloth/models/llama.py b/unsloth/models/llama.py
index ec6706e515..511ae5c681 100644
--- a/unsloth/models/llama.py
+++ b/unsloth/models/llama.py
@@ -724,7 +724,8 @@ def LlamaModel_fast_forward(
             past_key_values_length,
             sliding_window = getattr(self.config, "sliding_window", None),
         )
-        attention_mask = attention_mask.to(torch.bool)
+        if attention_mask is not None:
+            attention_mask = attention_mask.to(torch.bool)
     pass
 
     hidden_states = inputs_embeds