Patch PrintrboardG2 build (on spec)

Marlin/src/module/stepper.cpp

 
   #endif
 
-#else
+#else // PRINTRBOARD_G2
 
-  #include "../HAL/HAL_DUE/G2_PWM.h"
+  #include HAL_PATH(../HAL, fastio/G2_PWM.h)
 
 #endif
 

Marlin/src/pins/sam/pins_PRINTRBOARD_G2.h

 #define MOTOR_CURRENT_PWM_Y_PIN 64 // PB19        MOTOR 3
 #define MOTOR_CURRENT_PWM_E_PIN 61 // PA2         MOTOR 4
 
-//#define DEFAULT_PWM_MOTOR_CURRENT { 300, 400, 1000}  // XY Z E0, 1000 = 1000mAh
+#define DEFAULT_PWM_MOTOR_CURRENT { 300, 400, 1000}  // XY Z E0, 1000 = 1000mAh
 
 //
 // Temperature Sensors

config/examples/Printrbot/PrintrboardG2/Configuration.h

  *
  * :[-1, 0, 1, 2, 3, 4, 5, 6, 7]
  */
-#define SERIAL_PORT 0
+#define SERIAL_PORT -1
 
 /**
  * Select a secondary serial port on the board to use for communication with the host.