diff --git a/package/bcusdk/Config.in b/package/bcusdk/Config.in
index cf082e7dcb..c9a1947ebd 100644
--- a/package/bcusdk/Config.in
+++ b/package/bcusdk/Config.in
@@ -1,5 +1,6 @@
 config BR2_PACKAGE_BCUSDK
 	bool "bcusdk"
+	depends on BR2_USE_MMU # libpthsem
 	depends on BR2_INSTALL_LIBSTDCPP
 	select BR2_PACKAGE_LIBPTHSEM
 	help
diff --git a/package/libpthsem/Config.in b/package/libpthsem/Config.in
index 9ab13c3ed8..ae1c78f5ea 100644
--- a/package/libpthsem/Config.in
+++ b/package/libpthsem/Config.in
@@ -1,5 +1,6 @@
 config BR2_PACKAGE_LIBPTHSEM
 	bool "libpthsem"
+	depends on BR2_USE_MMU # fork()
 	select BR2_PACKAGE_ARGP_STANDALONE
 	help
 	  GNU pth is a user mode multi threading library. pthsem is an extend