diff --git a/flix/cli.ino b/flix/cli.ino
index 9a5c179..ad2cae0 100644
--- a/flix/cli.ino
+++ b/flix/cli.ino
@@ -6,8 +6,6 @@
 #include "pid.h"
 #include "vector.h"
 
-extern PID rollRatePID, pitchRatePID, yawRatePID, rollPID, pitchPID;
-extern LowPassFilter<Vector> ratesFilter;
 extern const int MOTOR_REAR_LEFT, MOTOR_REAR_RIGHT, MOTOR_FRONT_RIGHT, MOTOR_FRONT_LEFT;
 extern float loopRate;
 
diff --git a/flix/control.ino b/flix/control.ino
index dd92d7d..e81b686 100644
--- a/flix/control.ino
+++ b/flix/control.ino
@@ -30,8 +30,8 @@
 #define YAW_P 3
 #define PITCHRATE_MAX radians(360)
 #define ROLLRATE_MAX radians(360)
-#define YAWRATE_MAX radians(360)
-#define MAX_TILT radians(30)
+#define YAWRATE_MAX radians(300)
+#define TILT_MAX radians(30)
 
 #define RATES_D_LPF_ALPHA 0.2 // cutoff frequency ~ 40 Hz
 
@@ -92,8 +92,8 @@ void interpretRC() {
 		yawMode = controls[RC_CHANNEL_YAW] == 0 ? YAW : YAW_RATE;
 
 		attitudeTarget = Quaternion::fromEulerZYX(Vector(
-			controls[RC_CHANNEL_ROLL] * MAX_TILT,
-			controls[RC_CHANNEL_PITCH] * MAX_TILT,
+			controls[RC_CHANNEL_ROLL] * TILT_MAX,
+			controls[RC_CHANNEL_PITCH] * TILT_MAX,
 			attitudeTarget.getYaw()));
 		ratesTarget.z = -controls[RC_CHANNEL_YAW] * YAWRATE_MAX; // positive yaw stick means clockwise rotation in FLU
 
diff --git a/flix/failsafe.ino b/flix/failsafe.ino
index eab6ee5..4ff0066 100644
--- a/flix/failsafe.ino
+++ b/flix/failsafe.ino
@@ -8,14 +8,15 @@
 
 extern float controlsTime;
 
+// RC loss failsafe
 void failsafe() {
 	if (t - controlsTime > RC_LOSS_TIMEOUT) {
 		descend();
 	}
 }
 
+// Smooth descend on RC lost
 void descend() {
-	// Smooth descend on RC lost
 	mode = STAB;
 	controls[RC_CHANNEL_ROLL] = 0;
 	controls[RC_CHANNEL_PITCH] = 0;
diff --git a/flix/imu.ino b/flix/imu.ino
index f9c27d1..bf8a54f 100644
--- a/flix/imu.ino
+++ b/flix/imu.ino
@@ -7,11 +7,12 @@
 #include <MPU9250.h>
 #include "util.h"
 
+MPU9250 IMU(SPI);
+
 // NOTE: use 'ca' command to calibrate the accelerometer and put the values here
 Vector accBias(0, 0, 0);
 Vector accScale(1, 1, 1);
 
-MPU9250 IMU(SPI);
 Vector gyroBias;
 
 void setupIMU() {
diff --git a/flix/motors.ino b/flix/motors.ino
index 998af2c..6200b8c 100644
--- a/flix/motors.ino
+++ b/flix/motors.ino
@@ -2,8 +2,6 @@
 // Repository: https://github.com/okalachev/flix
 
 // Motors output control using MOSFETs
-// In case of using ESC, use this version of the code: https://gist.github.com/okalachev/8871d3a94b6b6c0a298f41a4edd34c61.
-// Motor: 8520 3.7V
 
 #include "util.h"
 
diff --git a/flix/rc.ino b/flix/rc.ino
index fe7b4d4..2f2c1ea 100644
--- a/flix/rc.ino
+++ b/flix/rc.ino
@@ -36,14 +36,14 @@ void normalizeRC() {
 }
 
 void calibrateRC() {
-	Serial.println("Calibrate RC: move all sticks to maximum positions in 4 seconds");
+	Serial.println("Calibrate RC: move all sticks to maximum positions [4 sec]");
 	Serial.println("··o     ··o\n···     ···\n···     ···");
 	delay(4000);
 	while (!readRC());
 	for (int i = 0; i < 16; i++) {
 		channelMax[i] = channels[i];
 	}
-	Serial.println("Calibrate RC: move all sticks to neutral positions in 4 seconds");
+	Serial.println("Calibrate RC: move all sticks to neutral positions [4 sec]");
 	Serial.println("···     ···\n···     ·o·\n·o·     ···");
 	delay(4000);
 	while (!readRC());