diff --git a/ports/unix/Makefile b/ports/unix/Makefile
index ae87a16252..8775ec11ac 100644
--- a/ports/unix/Makefile
+++ b/ports/unix/Makefile
@@ -149,6 +149,7 @@ SRC_C = \
 	alloc.c \
 	coverage.c \
 	fatfs_port.c \
+	supervisor/stub/serial.c \
 	supervisor/stub/stack.c \
 	supervisor/shared/translate.c \
 	$(SRC_MOD)