diff --git a/flix/control.ino b/flix/control.ino
index a87a340..b23c786 100644
--- a/flix/control.ino
+++ b/flix/control.ino
@@ -79,7 +79,7 @@ void interpretControls() {
 
 	if (mode == STAB) {
 		float yawTarget = attitudeTarget.getYaw();
-		if (invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target if NAN or yaw rate is set
+		if (invalid(yawTarget) || controlYaw != 0) yawTarget = attitude.getYaw(); // reset yaw target if NAN or pilot commands yaw rate
 		attitudeTarget = Quaternion::fromEuler(Vector(controlRoll * tiltMax, controlPitch * tiltMax, yawTarget));
 		ratesExtra = Vector(0, 0, -controlYaw * maxRate.z); // positive yaw stick means clockwise rotation in FLU
 	}
@@ -139,7 +139,7 @@ void controlTorque() {
 	if (!torqueTarget.valid()) return; // skip torque control
 
 	if (!armed || thrustTarget < 0.05) {
-		memset(motors, 0, sizeof(motors));
+		memset(motors, 0, sizeof(motors)); // stop motors if no thrust
 		return;
 	}
 
diff --git a/flix/failsafe.ino b/flix/failsafe.ino
index d62ce07..2c24d36 100644
--- a/flix/failsafe.ino
+++ b/flix/failsafe.ino
@@ -4,6 +4,8 @@
 // Fail-safe functions
 
 #define RC_LOSS_TIMEOUT 0.2
+#include "util.h"
+
 #define DESCEND_TIME 3.0 // time to descend from full throttle to zero
 
 extern double controlTime;
@@ -28,7 +30,7 @@ void autoFailsafe() {
 	static float roll, pitch, yaw, throttle;
 
 	if (roll != controlRoll || pitch != controlPitch || yaw != controlYaw || abs(throttle - controlThrottle) > 0.05) {
-		if (mode == AUTO && !isfinite(controlMode)) {
+		if (mode == AUTO && invalid(controlMode)) {
 			mode = STAB; // regain control to the pilot
 		}
 	}