diff --git a/grbl/config.h b/grbl/config.h
index ba82d01..076fd91 100644
--- a/grbl/config.h
+++ b/grbl/config.h
@@ -32,10 +32,10 @@
 
 
 // Define board type for pin map and default settings.
-#define CPU_MAP_SMOOTHIEBOARD   // Smoothieboard (NXP LPC1769 MCU)
+//#define CPU_MAP_SMOOTHIEBOARD   // Smoothieboard (NXP LPC1769 MCU)
 //#define CPU_MAP_C3D_REMIX       // Cohesion3D Remix (NXP LPC1769 MCU)
 //#define CPU_MAP_C3D_MINI        // Cohesion3D Mini (NXP LPC1769 MCU)
-//#define CPU_MAP_MKS_SBASE       // MKS SBASE Board (NXP LPC1768 MCU)
+#define CPU_MAP_MKS_SBASE       // MKS SBASE Board (NXP LPC1768 MCU)
 //#define CPU_MAP_AZTEEG_X5       // Azteeg X5 Board (NXP LPC1769 MCU)
 
 // Define machine type for machine specific defaults
diff --git a/grbl/cpu_map.h b/grbl/cpu_map.h
index d53f42c..5b8d412 100644
--- a/grbl/cpu_map.h
+++ b/grbl/cpu_map.h
@@ -190,8 +190,8 @@
   #define LIMIT_PORT        LPC_GPIO1->FIOPIN
   #define X_LIMIT_BIT       24  // X-MIN=24, X-MAX=25
   #define Y_LIMIT_BIT       26  // Y-MIN=26, Y-MAX=27
-  #define Z_LIMIT_BIT	    29  // Z-MIN=28, Z-MAX=29
-  #define A_LIMIT_BIT       28  // reuse p1.28, as z-min is not often used
+  #define Z_LIMIT_BIT	    28  // Z-MIN=28, Z-MAX=29
+  #define A_LIMIT_BIT       29  // reuse p1.29
   #define LIMIT_MASK       ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)|(1<<A_LIMIT_BIT)) // All limit bits
 
   // Define flood and mist coolant enable output pins.
@@ -490,8 +490,8 @@
   #define LIMIT_PORT        LPC_GPIO1->FIOPIN
   #define X_LIMIT_BIT       24  // X-MIN=24, X-MAX=25
   #define Y_LIMIT_BIT       26  // Y-MIN=26, Y-MAX=27
-  #define Z_LIMIT_BIT	    29  // Z-MIN=28, Z-MAX=29
-  #define A_LIMIT_BIT       28  // reuse p1.28, as z-min is not often used
+  #define Z_LIMIT_BIT	    28  // Z-MIN=28, Z-MAX=29
+  #define A_LIMIT_BIT       29  // reuse p1.29
   #define LIMIT_MASK       ((1<<X_LIMIT_BIT)|(1<<Y_LIMIT_BIT)|(1<<Z_LIMIT_BIT)|(1<<A_LIMIT_BIT)) // All limit bits
 
   // Define flood and mist coolant enable output pins.