diff --git a/ArduCopter/ArduCopter.pde b/ArduCopter/ArduCopter.pde
index aa765f5273..602d5fffac 100644
--- a/ArduCopter/ArduCopter.pde
+++ b/ArduCopter/ArduCopter.pde
@@ -1,6 +1,6 @@
 /// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
 
-#define THISFIRMWARE "ArduCopter V2.5"
+#define THISFIRMWARE "ArduCopter V2.5.1"
 /*
 ArduCopter Version 2.5
 Lead author:	Jason Short
diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index 3e9fa8d90a..8c489897f9 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -723,7 +723,7 @@
 // Throttle control gains
 //
 #ifndef THROTTLE_CRUISE
-# define THROTTLE_CRUISE	350		//
+# define THROTTLE_CRUISE	450		//
 #endif
 
 #ifndef ALT_HOLD_P
diff --git a/ArduCopter/navigation.pde b/ArduCopter/navigation.pde
index 221f665151..f74ffd58e1 100644
--- a/ArduCopter/navigation.pde
+++ b/ArduCopter/navigation.pde
@@ -5,7 +5,7 @@
 //****************************************************************
 static byte navigate()
 {
-	// waypoint distance from plane in meters
+	// waypoint distance from plane in cm
 	// ---------------------------------------
 	wp_distance 	= get_distance(&current_loc, &next_WP);
 	home_distance 	= get_distance(&current_loc, &home);
@@ -32,7 +32,7 @@ static bool check_missed_wp()
 	int32_t temp;
 	temp = target_bearing - original_target_bearing;
 	temp = wrap_180(temp);
-	return (abs(temp) > 10000);	//we pased the waypoint by 10 °
+	return (abs(temp) > 10000);	// we passed the waypoint by 100 degrees
 }
 
 // ------------------------------
@@ -529,7 +529,7 @@ static int32_t wrap_180(int32_t error)
 }
 */
 
-// distance is returned in meters
+// distance is returned in cm
 static int32_t get_distance(struct Location *loc1, struct Location *loc2)
 {
 	float dlat 		= (float)(loc2->lat - loc1->lat);
diff --git a/libraries/AC_PID/AC_PID.cpp b/libraries/AC_PID/AC_PID.cpp
index 3034468352..c09478c3fa 100755
--- a/libraries/AC_PID/AC_PID.cpp
+++ b/libraries/AC_PID/AC_PID.cpp
@@ -120,6 +120,7 @@ AC_PID::load_gains()
 	_ki.load();
 	_kd.load();
 	_imax.load();
+	_imax = abs(_imax);
 }
 
 void
diff --git a/libraries/AC_PID/AC_PID.h b/libraries/AC_PID/AC_PID.h
index b0ff88cfca..536317335b 100755
--- a/libraries/AC_PID/AC_PID.h
+++ b/libraries/AC_PID/AC_PID.h
@@ -33,7 +33,7 @@ public:
 		_kp  (initial_p),
 		_ki  (initial_i),
 		_kd  (initial_d),
-		_imax(initial_imax)
+		_imax(abs(initial_imax))
 	{
 		// no need for explicit load, assuming that the main code uses AP_Param::load_all.
 	}
@@ -78,7 +78,7 @@ public:
 	                 const float i,
 	                 const float d,
 	                 const int16_t imaxval) {
-		_kp = p; _ki = i; _kd = d; _imax = imaxval;
+		_kp = p; _ki = i; _kd = d; _imax = abs(imaxval);
 	}
 
 	float	kP() const				{ return _kp.get(); }