diff --git a/Makefile b/Makefile
index 4c3b44b..a6545e8 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@ LDFLAGS=-lstlink -lusb-1.0 -lsgutils2 -L.
 
 LIBRARY=libstlink.a
 
-all:  $(LIBRARY) test_usb test_sg 
+all:  $(LIBRARY) flash gdbserver test_usb test_sg 
 
 $(LIBRARY): $(OBJS_LIB)
 	@echo "objs are $(OBJS_LIB)"
@@ -42,5 +42,15 @@ clean:
 	rm -rf $(LIBRARY)
 	rm -rf test_usb*
 	rm -rf test_sg*
+
+distclean: clean
+	$(MAKE) -C flash clean
+	$(MAKE) -C gdbserver clean
 	
-.PHONY: clean all
+flash:
+	$(MAKE) -C flash
+
+gdbserver:
+	$(MAKE) -C gdbserver
+
+.PHONY: clean all flash gdbserver
diff --git a/example/blink_flash/Makefile b/example/blink_flash/Makefile
index d058390..7776471 100644
--- a/example/blink_flash/Makefile
+++ b/example/blink_flash/Makefile
@@ -5,7 +5,18 @@ CC=arm-none-eabi-gcc
 OBJCOPY=arm-none-eabi-objcopy
 
 CFLAGS=-O2 -mlittle-endian -mthumb
-CFLAGS+=-mcpu=cortex-m3 -ffreestanding -nostdlib -nostdinc
+
+CFLAGS=-g -O2 -mlittle-endian -mthumb
+ifeq ($(CONFIG_STM32L_DISCOVERY), 1)
+	CFLAGS+=-mcpu=cortex-m3 -DCONFIG_STM32L_DISCOVERY
+else ifeq ($(CONFIG_STM32VL_DISCOVERY), 1)
+	CFLAGS+=-mcpu=cortex-m3 -DCONFIG_STM32VL_DISCOVERY=1
+else ifeq ($(CONFIG_STM32F4_DISCOVERY), 1)
+	CFLAGS+=-mcpu=cortex-m4 -DCONFIG_STM32F4_DISCOVERY=1	
+else
+$(error "must specify CONFIG_ for board!")
+endif
+	CFLAGS+=-ffreestanding -nostdlib -nostdinc
 
 # to run from FLASH
 CFLAGS+=-Wl,-T,stm32_flash.ld
diff --git a/flash/main.c b/flash/main.c
index 3b9416d..a443f95 100644
--- a/flash/main.c
+++ b/flash/main.c
@@ -17,6 +17,11 @@ struct opts
   size_t size;
 };
 
+static void usage(void)
+{
+    puts("stlinkv1 command line: ./flash {read|write} /dev/sgX path addr <size>");
+    puts("stlinkv2 command line: ./flash {read|write} path addr <size>");
+}
 
 static int get_opts(struct opts* o, int ac, char** av)
 {
@@ -75,6 +80,7 @@ int main(int ac, char** av)
   if (get_opts(&o, ac - 1, av + 1) == -1)
   {
     printf("invalid command line\n");
+    usage();
     goto on_error;
   }
 
@@ -86,7 +92,7 @@ int main(int ac, char** av)
   }
   else /* stlinkv2 */
   {
-    sl = stlink_open_usb(NULL, 10);
+    sl = stlink_open_usb(10);
     if (sl == NULL) goto on_error;
   }