diff --git a/README.adoc b/README.adoc
index 7048b62..ab94a8d 100644
--- a/README.adoc
+++ b/README.adoc
@@ -31,6 +31,8 @@ cd linux-kernel-module-cheat
 ./configure && ./build && ./run
 ....
 
+It does not work if you just download the .zip from GitHub because we use Git submodules, you must clone this repo. `./configure` then fetches only the required submodules for you.
+
 It is also trivial to build for different supported <<cpu-architecture,CPU architectures>>.
 
 The first configure will take a while (30 minutes to 2 hours) to clone and build, see <<benchmark-builds>> for more details.