diff --git a/tools/cmake/build.cmake b/tools/cmake/build.cmake
index bbd4d16fe9..e89e114e01 100644
--- a/tools/cmake/build.cmake
+++ b/tools/cmake/build.cmake
@@ -313,7 +313,7 @@ endmacro()
 #
 macro(__build_set_default var default)
     set(_var __${var})
-    if(NOT "${_var}" STREQUAL "")
+    if(NOT "${${_var}}" STREQUAL "")
         idf_build_set_property(${var} "${${_var}}")
     else()
         idf_build_set_property(${var} "${default}")