diff --git a/Makefile b/Makefile
index 7b5c29d..075b4bb 100644
--- a/Makefile
+++ b/Makefile
@@ -5,11 +5,16 @@ CC_FLAGS = -mmcs51
 ASM = sdas8051
 AFLAGS= -plosgff
 
-all: rtlplayground.bin injector
+SUBDIRS := uip
+
+all: $(SUBDIRS) rtlplayground.bin injector
 
 SRCS= rtlplayground.c rtl837x_flash.c rtl837x_phy.c rtl837x_port.c cmd_parser.c
 OBJS= ${SRCS:.c=.rel}
 
+$(SUBDIRS):
+	$(MAKE) -C $@
+
 clean:
 	if [ -e rtlplayground.bin ]; then rm rtlplayground.bin; fi
 	if [ -e rtlplayground.asm ]; then rm rtlplayground.asm; fi
@@ -38,5 +43,5 @@ rtlplayground.ihx:  crtstart.rel $(OBJS)
 injector: injector.c
 	gcc $^ -o $@
 
-.PHONY: clean all
+.PHONY: clean all $(SUBDIRS)
 .PRECIOUS: %.rel %.ihx .img