diff --git a/Makefile b/Makefile
index 9350656..ee94cb5 100644
--- a/Makefile
+++ b/Makefile
@@ -29,7 +29,7 @@ GRBL_OVERRIDE_OBJECTS =  ../main.o ../serial.o ../report.o
 AVR_OBJECTS  = avr/interrupt.o avr/pgmspace.o  avr/io.o  avr/eeprom.o grbl_eeprom_extensions.o
 
 # Simulator Only Objects
-SIM_OBJECTS = main.o simulator.o serial.o util/delay.o util/floatunsisf.o platform_$(PLATFORM).o system_declares.o
+SIM_OBJECTS = main.o simulator.o serial.o util/delay.o util/floatunsisf.o platform_$(PLATFORM).o
 
 GRBL_SIM_OBJECTS = grbl_interface.o  $(GRBL_BASE_OBJECTS) $(GRBL_OVERRIDE_OBJECTS) $(SIM_OBJECTS) $(AVR_OBJECTS)
 GRBL_VAL_OBJECTS = validator.o overridden_report.o $(GRBL_BASE_OBJECTS) $(AVR_OBJECTS) system_declares.o
diff --git a/avr/wdt.h b/avr/wdt.h
index 4582a82..15a8e4c 100644
--- a/avr/wdt.h
+++ b/avr/wdt.h
@@ -20,7 +20,7 @@
   along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#define WDTCSR wdt
+/*#define WDTCSR wdt*/
 #define WDP0 0
 #define WDP1 1
 #define WDP2 2
@@ -30,4 +30,4 @@
 #define WDIE 6
 #define WDIF 7
 
-uint16_t wdt;
+/*uint16_t wdt;*/
diff --git a/validator.c b/validator.c
index 0c9988a..8dde9f9 100644
--- a/validator.c
+++ b/validator.c
@@ -37,7 +37,7 @@
 
 // Declare system global variable structure
 system_t sys; 
-volatile io_sim_t io;
+/*volatile io_sim_t io;*/
 
 
 typedef struct arg_vars {