diff --git a/README.md b/README.md
index 7254b2c9..070b1d9c 100644
--- a/README.md
+++ b/README.md
@@ -73,7 +73,7 @@ We additionally provide a [FAISS](https://github.com/facebookresearch/faiss) ind
 
 
 To build and save FAISS (exact search) index yourself, run
-`python blink/build_faiss_index.py --output_path models/faiss_flat_index.pkl`
+`python blink/build_faiss_index.py --output_path models/faiss_flat_index.pkl --save_index`
 
 
 ### 3. Use BLINK interactively
diff --git a/requirements.txt b/requirements.txt
index 9e23a0cc..7a021322 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,3 +13,4 @@ transformers==3.1.0
 colorama==0.4.3
 termcolor==1.1.0
 faiss-cpu>=1.6.1
+gensim<4.0