diff --git a/gpu/README.md b/gpu/README.md
index cf2d5bb..5c9c899 100644
--- a/gpu/README.md
+++ b/gpu/README.md
@@ -2,3 +2,4 @@ gpu
 =======
 
 example of how to use the GPU with ctrulib
+before trying to compile, make sure to download aemstro ( https://github.com/smealum/aemstro ) and update Makefile's AEMSTROPATH definition with the proper path