solved problem with floating buttons, limit of maximum velocity.

Marlin/Configuration.h

@@ -134,7 +134,7 @@ double Kd = 80/PID_dT;
 // hooke's law says:		force = k * distance
 // bernoulli's priniciple says:	v ^ 2 / 2 + g . h + pressure / density = constant
 // so: v ^ 2 is proportional to number of steps we advance the extruder
-#define ADVANCE
+//#define ADVANCE
 
 #ifdef ADVANCE
 #define EXTRUDER_ADVANCE_K 0.02

Marlin/buttons.pde

@@ -94,6 +94,7 @@ void buttons_init()
   pinMode(SHIFT_LD,OUTPUT); 
   pinMode(SHIFT_EN,OUTPUT);
   pinMode(SHIFT_OUT,INPUT); 
+	digitalWrite(SHIFT_OUT,HIGH);
   digitalWrite(SHIFT_LD,HIGH);  //load has inverse logic
   digitalWrite(SHIFT_EN,LOW);  //low active
 }