--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,8 @@ AR      = $(CROSS)ar
 STRIP   = $(CROSS)strip
 OBJCOPY = $(CROSS)objcopy
 WINDRES = $(CROSS)windres
-CFLAGS  = -Wall -ggdb -I. -IWpdPack/Include/ -fno-strict-aliasing -fpack-struct -Os
+OFLAGS  = -Os -ggdb
+CFLAGS  = -Wall -I. -IWpdPack/Include/ -fno-strict-aliasing -fpack-struct $(OFLAGS)
 LIB_OBJS= ap51-flash.o uip.o uip_arp.o timer.o clock-arch.o psock.o packet.o
 OBJS    = $(LIB_OBJS) main.o
 AP51_RC = ap51-flash-res