diff --git a/grbl-lpc/avr/io.h b/grbl-lpc/avr/io.h
index 1e4e5ee..c622455 100644
--- a/grbl-lpc/avr/io.h
+++ b/grbl-lpc/avr/io.h
@@ -8,64 +8,7 @@ struct DummyReg {
     uint8_t operator|=(uint8_t x) {return *this = *this | x;}
 };
 
-extern DummyReg DDRA;
-extern DummyReg DDRB;
-extern DummyReg DDRC;
-extern DummyReg DDRD;
-
-extern DummyReg PORTA;
-extern DummyReg PORTB;
-extern DummyReg PORTC;
-extern DummyReg PORTD;
-
-extern DummyReg PINA;
-extern DummyReg PINB;
-extern DummyReg PINC;
-extern DummyReg PIND;
-
-extern DummyReg EEAR;
-extern DummyReg EECR;
-extern DummyReg EEDR;
-extern DummyReg EEMPE;
-extern DummyReg EEPE;
-extern DummyReg OCR2A;
+extern DummyReg NotUsed;
 extern DummyReg PCICR;
-extern DummyReg PCIE0;
 extern DummyReg PCIE1;
-extern DummyReg PCMSK0;
-extern DummyReg PCMSK1;
-extern DummyReg TCCR2A;
-extern DummyReg TCCR2B;
 
-extern DummyReg UCSR0A;
-extern DummyReg UCSR0B;
-extern DummyReg U2X0;
-extern DummyReg UBRR0H;
-extern DummyReg UBRR0L;
-extern DummyReg UDR0;
-
-
-static const int COM1A0 = 0;
-static const int COM1A1 = 0;
-static const int COM1B0 = 0;
-static const int COM1B1 = 0;
-static const int COM2A0 = 0;
-static const int COM2A1 = 0;
-static const int COM2B0 = 0;
-static const int COM2B1 = 0;
-
- static const int CS22 = 0;
-static const int EEMWE = 0;
-static const int EERE = 0;
-static const int EEWE = 0;
-static const int WGM10 = 0;
-static const int WGM11 = 0;
-static const int WGM12 = 0;
-static const int WGM13 = 0;
-static const int WGM20 = 0;
-static const int WGM21 = 0;
-
-static const int RXEN0 = 0;
-static const int TXEN0 = 0;
-static const int RXCIE0 = 0;
-static const int UDRIE0 = 0;
diff --git a/grbl/config.h b/grbl/config.h
index 3396771..91f5932 100644
--- a/grbl/config.h
+++ b/grbl/config.h
@@ -677,32 +677,32 @@
 */
 
 // Define flood and mist coolant enable output pins.
-#define COOLANT_FLOOD_DDR   DDRC
-#define COOLANT_FLOOD_PORT  PORTC
+#define COOLANT_FLOOD_DDR   NotUsed
+#define COOLANT_FLOOD_PORT  NotUsed
 #define COOLANT_FLOOD_BIT   3  // Uno Analog Pin 3
-#define COOLANT_MIST_DDR   DDRC
-#define COOLANT_MIST_PORT  PORTC
+#define COOLANT_MIST_DDR   NotUsed
+#define COOLANT_MIST_PORT  NotUsed
 #define COOLANT_MIST_BIT   4  // Uno Analog Pin 3
 
 // Define user-control controls (cycle start, reset, feed hold) input pins.
 // NOTE: All CONTROLs pins must be on the same port and not on a port with other input pins (limits).
-#define CONTROL_DDR       DDRC
-#define CONTROL_PIN       PINC
-#define CONTROL_PORT      PORTC
+#define CONTROL_DDR       NotUsed
+#define CONTROL_PIN       NotUsed
+#define CONTROL_PORT      NotUsed
 #define CONTROL_RESET_BIT         0  // Uno Analog Pin 0
 #define CONTROL_FEED_HOLD_BIT     1  // Uno Analog Pin 1
 #define CONTROL_CYCLE_START_BIT   2  // Uno Analog Pin 2
 #define CONTROL_SAFETY_DOOR_BIT   1  // Uno Analog Pin 1 NOTE: Safety door is shared with feed hold. Enabled by config define.
 #define CONTROL_INT       PCIE1  // Pin change interrupt enable pin
 #define CONTROL_INT_vect  PCINT1_vect
-#define CONTROL_PCMSK     PCMSK1 // Pin change interrupt register
+#define CONTROL_PCMSK     NotUsed // Pin change interrupt register
 #define CONTROL_MASK      ((1<<CONTROL_RESET_BIT)|(1<<CONTROL_FEED_HOLD_BIT)|(1<<CONTROL_CYCLE_START_BIT)|(1<<CONTROL_SAFETY_DOOR_BIT))
 #define CONTROL_INVERT_MASK   CONTROL_MASK // May be re-defined to only invert certain control pins.
 
 // Define probe switch input pin.
-#define PROBE_DDR       DDRC
-#define PROBE_PIN       PINC
-#define PROBE_PORT      PORTC
+#define PROBE_DDR       NotUsed
+#define PROBE_PIN       NotUsed
+#define PROBE_PORT      NotUsed
 #define PROBE_BIT       5  // Uno Analog Pin 5
 #define PROBE_MASK      (1<<PROBE_BIT)
 
diff --git a/grbl/main.c b/grbl/main.c
index 8d5ec93..ec26796 100644
--- a/grbl/main.c
+++ b/grbl/main.c
@@ -24,41 +24,9 @@
 void isr_init();
 
 /*Holding space for dummy registers*/
-DummyReg DDRA;
-DummyReg DDRB;
-DummyReg DDRC;
-DummyReg DDRD;
-
-DummyReg PORTA;
-DummyReg PORTB;
-DummyReg PORTC;
-DummyReg PORTD;
-
-DummyReg PINA;
-DummyReg PINB;
-DummyReg PINC;
-DummyReg PIND;
-
-DummyReg EEAR;
-DummyReg EECR;
-DummyReg EEDR;
-DummyReg EEMPE;
-DummyReg EEPE;
-DummyReg OCR2A;
-DummyReg PCICR;
-DummyReg PCIE0;
-DummyReg PCIE1;
-DummyReg PCMSK0;
-DummyReg PCMSK1;
-DummyReg TCCR2A;
-DummyReg TCCR2B;
-
-DummyReg UCSR0A;
-DummyReg UCSR0B;
-DummyReg U2X0;
-DummyReg UBRR0H;
-DummyReg UBRR0L;
-DummyReg UDR0;
+extern DummyReg NotUsed;
+extern DummyReg PCICR;
+extern DummyReg PCIE1;
 
 // Declare system global variable structure
 system_t sys;
diff --git a/grbl/serial.c b/grbl/serial.c
index 85eff99..c2ee127 100644
--- a/grbl/serial.c
+++ b/grbl/serial.c
@@ -112,6 +112,7 @@ void serial_init()
 #endif
 }
 
+/*
 void legacy_serial_init()
 {
   // Set baud rate
@@ -130,6 +131,7 @@ void legacy_serial_init()
 
   // defaults to 8-bit, no parity, 1 stop bit
 }
+*/
 
 // Writes one byte to the TX serial buffer. Called by main program.
 void serial_write(uint8_t data) {
@@ -154,7 +156,7 @@ void serial_write(uint8_t data) {
   serialDriver.Send(serial_tx_buffer, 1);
 #endif
 }
-
+/*
 // Writes one byte to the TX serial buffer. Called by main program.
 void legacy_serial_write(uint8_t data) {
   // Calculate next head
@@ -174,7 +176,7 @@ void legacy_serial_write(uint8_t data) {
   // Enable Data Register Empty Interrupt to make sure tx-streaming is running
   UCSR0B |=  (1 << UDRIE0);
 }
-
+*/
 //Device driver interrupt
 // The CMSIS Driver doesn't have seperate interrupts/callbacks available for TX and RX but instead
 // is a single composite interrupt.
@@ -190,6 +192,7 @@ void serialInterrupt(uint32_t event) {
 
 //We don't use TX interrupts directly with the ARM Driver.
 // Data Register Empty Interrupt handler
+/*
 void legacy_TX_ISR(void* SERIAL_UDRE)
 {
   uint8_t tail = serial_tx_buffer_tail; // Temporary serial_tx_buffer_tail (to optimize for volatile)
@@ -206,7 +209,7 @@ void legacy_TX_ISR(void* SERIAL_UDRE)
   // Turn off Data Register Empty Interrupt to stop tx-streaming if this concludes the transfer
   if (tail == serial_tx_buffer_head) { UCSR0B &= ~(1 << UDRIE0); }
 }
-
+*/
 
 // Fetches the first byte in the serial read buffer. Called by main program.
 uint8_t serial_read()