diff --git a/package/linknx/Config.in b/package/linknx/Config.in
index 18e98677b7..f35351e688 100644
--- a/package/linknx/Config.in
+++ b/package/linknx/Config.in
@@ -2,6 +2,7 @@ config BR2_PACKAGE_LINKNX
 	bool "linknx"
 	select BR2_PACKAGE_LIBPTHSEM
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_USE_MMU # libpthsem
 	help
 	  Linknx is an automation platform providing high level functionalities
 	  to EIB/KNX installation.