diff --git a/demo/nesa/download.py b/demo/nesa/download.py
index 7a4a4c6..ff1e85b 100644
--- a/demo/nesa/download.py
+++ b/demo/nesa/download.py
@@ -286,8 +286,10 @@ def check_model_files(self, model, branch, links, sha256, output_folder):
                 continue
 
             with open(output_folder / sha256[i][0], "rb") as f:
-                bytes = f.read()
-                file_hash = hashlib.sha256(bytes).hexdigest()
+                hasher = hashlib.sha256()
+                for chunk in iter(lambda: f.read(8192), b""):
+                    hasher.update(chunk)
+                file_hash = hasher.hexdigest()
                 if file_hash != sha256[i][1]:
                     print(f'Checksum failed: {sha256[i][0]}  {sha256[i][1]}')
                     validated = False