diff --git a/sim/mcuboot-sys/build.rs b/sim/mcuboot-sys/build.rs
index 7db37f1..c67b792 100644
--- a/sim/mcuboot-sys/build.rs
+++ b/sim/mcuboot-sys/build.rs
@@ -90,7 +90,7 @@
 
     walk_dir("../../boot").unwrap();
     walk_dir("../../ext/tinycrypt/lib/source").unwrap();
-    walk_dir("../../ext/mbedtls/src").unwrap();
+    walk_dir("../../ext/mbedtls").unwrap();
     walk_dir("csupport").unwrap();
     walk_dir("mbedtls/include").unwrap();
     walk_dir("mbedtls/library").unwrap();