diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 6f61ee9..83b646c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,7 +25,7 @@ jobs:
       - name: Build firmware
         working-directory: app
         run: |
-          west build -b nrf52840dk_nrf52840 -s app
+          west build -b nrf52840dk/nrf52840 -s app
 
       - name: Archive firmware
         uses: actions/upload-artifact@v2
diff --git a/app/boards/nrf52840dk_nrf52840.overlay b/app/boards/nrf52840dk_nrf52840.overlay
index 4c22cb7..2fe5e26 100644
--- a/app/boards/nrf52840dk_nrf52840.overlay
+++ b/app/boards/nrf52840dk_nrf52840.overlay
@@ -18,6 +18,7 @@
 };
 
 &uart1 {
+	status = "okay";
 	#address-cells = <1>;
 	#size-cells = <0>;
 
diff --git a/app/src/main.c b/app/src/main.c
index 9aaf6bf..734a251 100644
--- a/app/src/main.c
+++ b/app/src/main.c
@@ -186,7 +186,7 @@ void fp_trig_handler(const struct device *dev,
  * Entry point
  ******************************************************************************/
 
-void main(void)
+int main(void)
 {
 	int ret;
 	const struct sensor_trigger trig = {
@@ -196,12 +196,12 @@ void main(void)
 
 	if (!device_is_ready(fpreader)) {
 		printk("Fingerprint reader not ready");
-		return;
+		return 0;
 	}
 
 	if (!device_is_ready(lock)) {
 		printk("Lock not ready");
-		return;
+		return 0;
 	}
 
 	/* run enroll (will be skipped if sw0 is not pressed) */
@@ -217,13 +217,15 @@ void main(void)
 	ret = bt_enable(NULL);
 	if (ret < 0) {
 		printk("Bluetooth init failed (ret %d)\n", ret);
-		return;
+		return 0;
 	}
 
 	ret = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd,
 			      ARRAY_SIZE(sd));
 	if (ret < 0) {
 		printk("Advertising failed to start (%d)", ret);
-		return;
+		return 0;
 	}
+
+	return 0;
 }
diff --git a/drivers/lock/Kconfig.servo b/drivers/lock/Kconfig.servo
index 859b219..e9d0a20 100644
--- a/drivers/lock/Kconfig.servo
+++ b/drivers/lock/Kconfig.servo
@@ -1,6 +1,8 @@
 config LOCK_SERVO
 	bool "Servo-controlled lock"
 	default y
-	depends on PWM && ADC && DT_HAS_LOCK_SERVO_ENABLED
+	depends on DT_HAS_LOCK_SERVO_ENABLED
+	select PWM
+	select ADC
 	help
 	  Enables a servo-controlled lock driver.
diff --git a/drivers/sensor/jm101/Kconfig b/drivers/sensor/jm101/Kconfig
index 3ee10a6..ee15393 100644
--- a/drivers/sensor/jm101/Kconfig
+++ b/drivers/sensor/jm101/Kconfig
@@ -4,7 +4,10 @@
 config JM101
 	bool "JM-101 fingerprint sensor"
 	default y
-	depends on GPIO && SERIAL && UART_INTERRUPT_DRIVEN && DT_HAS_ZEANTEC_JM101_ENABLED
+	depends on DT_HAS_ZEANTEC_JM101_ENABLED
+	select GPIO
+	select SERIAL
+	select UART_INTERRUPT_DRIVEN
 	help
 	  JM-101 fingerprint sensor.