diff --git a/tests/scripts/components-build-system.sh b/tests/scripts/components-build-system.sh
index a086d5ecce..2c2d46004e 100644
--- a/tests/scripts/components-build-system.sh
+++ b/tests/scripts/components-build-system.sh
@@ -65,7 +65,7 @@ component_test_cmake_out_of_source () {
     mkdir "$OUT_OF_SOURCE_DIR"
     cd "$OUT_OF_SOURCE_DIR"
     # Note: Explicitly generate files as these are turned off in releases
-    cmake -D CMAKE_BUILD_TYPE:String=Check -D GEN_FILES=ON _D TEST_CPP=1 "$MBEDTLS_ROOT_DIR"
+    cmake -D CMAKE_BUILD_TYPE:String=Check -D GEN_FILES=ON -D TEST_CPP=1 "$MBEDTLS_ROOT_DIR"
     make
 
     msg "test: cmake 'out-of-source' build"