Adjusted the features for the debug buid:

Removed DEBUG_DISABLE_STARTMSGS. This macro defeats the purpose
of the build server and the build messages of the non-release builds.

Removed DEBUG_DUMP_TO_2ND_SERIAL for performance reasons.

Firmware/Configuration_prusa.h

@@ -119,7 +119,7 @@ const bool Z_MIN_ENDSTOP_INVERTING = false; // set to true to invert the logic o
 //#define DEBUG_DISABLE_YMAXLIMIT  //y max limit ignored
 //#define DEBUG_DISABLE_ZMINLIMIT  //z min limit ignored
 //#define DEBUG_DISABLE_ZMAXLIMIT  //z max limit ignored
-#define DEBUG_DISABLE_STARTMSGS //no startup messages 
+//#define DEBUG_DISABLE_STARTMSGS //no startup messages 
 //#define DEBUG_DISABLE_MINTEMP   //mintemp error ignored
 //#define DEBUG_DISABLE_SWLIMITS  //sw limits ignored
 //#define DEBUG_DISABLE_LCD_STATUS_LINE  //empty four lcd line
@@ -130,7 +130,7 @@ const bool Z_MIN_ENDSTOP_INVERTING = false; // set to true to invert the logic o
 //#define DEBUG_BLINK_ACTIVE
 //#define DEBUG_DISABLE_FANCHECK     //disable fan check (no ISR INT7, check disabled)
 //#define DEBUG_DISABLE_FSENSORCHECK //disable fsensor check (no ISR INT7, check disabled)
-#define DEBUG_DUMP_TO_2ND_SERIAL   //dump received characters to 2nd serial line
+//#define DEBUG_DUMP_TO_2ND_SERIAL   //dump received characters to 2nd serial line
 #define DEBUG_STEPPER_TIMER_MISSED // Stop on stepper timer overflow, beep and display a message.
 #define PLANNER_DIAGNOSTICS // Show the planner queue status on printer display.
 #endif /* DEBUG_BUILD */