diff --git a/cc3200/application.mk b/cc3200/application.mk
index 5b81f7228c..0f393bd541 100644
--- a/cc3200/application.mk
+++ b/cc3200/application.mk
@@ -158,6 +158,7 @@ APP_LIB_SRC_C = $(addprefix lib/,\
 APP_STM_SRC_C = $(addprefix stmhal/,\
 	bufhelper.c \
 	file.c \
+	builtin_open.c \
 	import.c \
 	input.c \
 	irq.c \