diff --git a/stm-firmware/main.c b/stm-firmware/main.c
index 0038bc9..82a2652 100644
--- a/stm-firmware/main.c
+++ b/stm-firmware/main.c
@@ -73,6 +73,11 @@ FATFS *fs_ptr = &fs;
 
 static inline void uart_gpio_config()
 {
+	/*
+	 * In case the application is build in debug mode, use the TX/RX Pins on the debug header
+	 * else the Pins on the DIGIO header are configured in the digio module
+	 */
+
 #ifdef DEBUGBUILD
 	rcc_manager_enable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(SHELL_UART_PORT_RCC_MASK));
 	SHELL_UART_PORT->MODER &=  MODER_DELETE(SHELL_UART_TX_PIN) & MODER_DELETE(SHELL_UART_RX_PIN);
@@ -151,7 +156,15 @@ static inline int32_t handle_pid_controller(struct pid_controller *pid, float ta
 	return pid_out;
 }
 
-const char *oven_controller_hello_world = "Hello world :)\n";
+static void setup_unused_pins()
+{
+	int i;
+
+	rcc_manager_enable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(RCC_AHB1ENR_GPIOEEN));
+	GPIOE->MODER = 0UL;
+	for (i = 0; i < 16; i++)
+		GPIOE->PUPDR |= PULLDOWN(i);
+}
 
 static inline void setup_system()
 {
@@ -169,16 +182,26 @@ static inline void setup_system()
 
 	uart_gpio_config();
 	setup_sell_uart(&shell_uart);
+
+	setup_unused_pins();
+}
+
+static void handle_shell_uart_input(shellmatta_handle_t shell_handle)
+{
+	int uart_receive_status;
+	const char *uart_input;
+	size_t uart_input_len;
+
+	/* Handle uart input for shell */
+	uart_receive_status = uart_receive_data_with_dma(&shell_uart, &uart_input, &uart_input_len);
+	if (uart_receive_status >= 0)
+		shell_handle_input(shell_handle, uart_input, uart_input_len);
 }
 
 int main()
 {
 	bool sd_card_mounted = false;
-	FIL test_file;
-	const char *uart_input;
-	size_t uart_input_len;
 	shellmatta_handle_t shell_handle;
-	int uart_receive_status;
 
 	uint64_t pid_timestamp = 0ULL;
 	bool pid_controller_active = false;
@@ -194,13 +217,6 @@ int main()
 	shell_handle = shell_init(write_shell_callback);
 	shell_print_motd(shell_handle);
 
-	if (f_mount(fs_ptr, "0:/", 1) == FR_OK) {
-		sd_card_mounted = true;
-		f_open(&test_file, "hello-world.txt", FA_OPEN_APPEND | FA_WRITE);
-		f_write(&test_file, oven_controller_hello_world, strlen(oven_controller_hello_world), NULL);
-		f_close(&test_file);
-	}
-
 	pid_init(&pid, 0.1, 0.1, 4.0, 0.0, 100.0, 40.0);
 	pid_zero(&pid);
 
@@ -219,6 +235,8 @@ int main()
 			/* Blink red led in case of temp error */
 			if (pt1000_value_status < 0)
 				led_set(0, !led_get(0));
+			else
+				led_set(0, 0);
 		}
 
 		/* Handle error in case PID controller should be active, but temperature measurement failed */
@@ -243,10 +261,7 @@ int main()
 		snprintf(&disp[1][0], 17, "Rotary: %u", (unsigned int)rot);
 		snprintf(&disp[2][0], 17, "Button: %s", (button == BUTTON_SHORT ? "SHORT" : (button == BUTTON_LONG ? "LONG" : "")));
 
-		/* Handle uart input for shell */
-		uart_receive_status = uart_receive_data_with_dma(&shell_uart, &uart_input, &uart_input_len);
-		if (uart_receive_status >= 0)
-			shell_handle_input(shell_handle, uart_input, uart_input_len);
+		handle_shell_uart_input(shell_handle);
 
 		if (systick_ticks_have_passed(display_timestamp, 2) || lcd_ret == LCD_FSM_CALL_AGAIN) {
 			lcd_ret = lcd_fsm_write_buffer(disp);