diff --git a/doc/INSTALL.md b/doc/INSTALL.md
index ec6aeb02be0a..0d6505e241c0 100644
--- a/doc/INSTALL.md
+++ b/doc/INSTALL.md
@@ -58,7 +58,7 @@ Clone lightning:
 For development or running tests, get additional dependencies:
 
     sudo apt-get install -y valgrind python3-pip libpq-dev
-    sudo pip3 install -r requirements.txt
+    sudo pip3 install -r requirements.txt --use-feature=in-tree-build
 
 Build lightning: