diff --git a/projects/rfdsatt/rfdsatt.c b/projects/rfdsatt/rfdsatt.c
index 39c4a24..2689fae 100644
--- a/projects/rfdsatt/rfdsatt.c
+++ b/projects/rfdsatt/rfdsatt.c
@@ -143,7 +143,11 @@ static void usart_setup(void)
 static void gpio_setup(void)
 {
 #ifdef STM32F1
-	/* Set GPIO15 (in GPIO port B) to 'output push-pull'. */
+	/* disable JTAG, keep SWJ-DP (we use some related GPIOs) */
+	rcc_periph_clock_enable(RCC_AFIO);
+	gpio_primary_remap(AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_ON, 0);
+
+	/* Set GPIO15 (in GPIO port B) to 'output push-pull' for the LED. */
 	gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ,
 		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO15);
 #else