diff --git a/avr/cores/microcore/Arduino.h b/avr/cores/microcore/Arduino.h
index f39d46d5..6d4a7217 100644
--- a/avr/cores/microcore/Arduino.h
+++ b/avr/cores/microcore/Arduino.h
@@ -115,38 +115,6 @@ extern "C"{
   void loop(void);
   void yield(void) __attribute__ ((weak, alias("__empty")));
   static void __empty() { /* Empty*/ }
-
-  // Constant checks error handler
-  void badArg(const char*) __attribute__((error("")));
-  #define ASSERT_CONST(pin) \
-    if(!__builtin_constant_p(pin)) badArg("Pin must be a constant")
-
-  // Check for valid PWM pin (0 .. 5)
-  __attribute__((always_inline))
-  inline void check_valid_digital_pin(uint8_t pin)
-  {
-    if(__builtin_constant_p(pin))
-    {
-      if(pin >= NUM_DIGITAL_PINS)
-        badArg("Digtial pin out of range");
-    }
-    else
-      badArg("Digital pin must be a constant");
-  }
-
-  // Check for valid PWM pin (0 .. 1)
-  __attribute__((always_inline))
-  inline void check_valid_pwm_pin(uint8_t pin)
-  {
-    if(__builtin_constant_p(pin))
-    {
-      if(pin > 1)
-        badArg("PWM pin out of range");
-    }
-    else
-      badArg("PWM pin must be a constant");
-  }
-
 #ifdef __cplusplus
 } // extern "C"
 
diff --git a/avr/cores/microcore/wiring_digital.c b/avr/cores/microcore/wiring_digital.c
index 7f2835a0..4e59029c 100644
--- a/avr/cores/microcore/wiring_digital.c
+++ b/avr/cores/microcore/wiring_digital.c
@@ -1,10 +1,10 @@
 /*** MicroCore - wiring_digital.c ***
 An Arduino core designed for ATtiny13
-Based on the work done by "smeezekitty" 
+Based on the work done by "smeezekitty"
 Modified and maintained by MCUdude
 https://github.com/MCUdude/MicroCore
 
-This file contains digital related 
+This file contains digital related
 functions such as pinMode(),
 digitalWrite() and digitalRead().
 */
@@ -13,11 +13,9 @@ digitalWrite() and digitalRead().
 
 void pinMode(uint8_t pin, uint8_t mode)
 {
- check_valid_digital_pin(pin);
-  
   if(mode == OUTPUT) // Pin as output
     DDRB |= _BV(pin);
-      
+
   else // Pin as input or input pullup
   {
     DDRB &= ~_BV(pin); // Set pin as input
@@ -26,11 +24,8 @@ void pinMode(uint8_t pin, uint8_t mode)
   }
 }
 
-
 void digitalWrite(uint8_t pin, uint8_t val)
 {
-  check_valid_digital_pin(pin);
-    
   if(val)
     PORTB |= _BV(pin);  // Set pin high
   else
@@ -40,7 +35,5 @@ void digitalWrite(uint8_t pin, uint8_t val)
 
 uint8_t digitalRead(uint8_t pin)
 {
-  check_valid_digital_pin(pin);
-  
   return !!(PINB & _BV(pin));
 }
diff --git a/avr/cores/microcore/wiring_pulse.c b/avr/cores/microcore/wiring_pulse.c
index f2c5b285..3f34ad6b 100644
--- a/avr/cores/microcore/wiring_pulse.c
+++ b/avr/cores/microcore/wiring_pulse.c
@@ -21,13 +21,6 @@ dozen microseconds before the start of the pulse.
 // However it will only work properly with LTO enabled.
 uint32_t pulseIn(uint8_t pin, uint8_t state, uint32_t timeout)
 {
-  check_valid_digital_pin(pin);
-
-  #if defined(SAFEMODE)
-    if(pin < 2)
-      turnOffPWM(c); // If it's a PWM pin, make sure PWM is off
-  #endif
-
   // Convert the timeout from microseconds to a number of times through
   // the initial loop; it takes 16 clock cycles per iteration.
   uint32_t numloops = 0;
diff --git a/avr/cores/microcore/wiring_pwm.c b/avr/cores/microcore/wiring_pwm.c
index bae6e97e..e0cce6f1 100644
--- a/avr/cores/microcore/wiring_pwm.c
+++ b/avr/cores/microcore/wiring_pwm.c
@@ -13,19 +13,14 @@ analogWrite().
 
 void turnOffPWM(uint8_t pin)
 {
-  check_valid_pwm_pin(pin);
-
   if(pin == 0)
     TCCR0A &= ~_BV(COM0A1);
   else
     TCCR0A &= ~_BV(COM0B1);
 }
 
-
 void analogWrite(uint8_t pin, uint8_t val)
 {
-  check_valid_pwm_pin(pin);
-
   // Set Timer0 prescaler
   #if !defined(ENABLE_MICROS)
     #if defined(PWM_PRESCALER_NONE)     // PWM frequency = (F_CPU/256) / 1
@@ -47,7 +42,8 @@ void analogWrite(uint8_t pin, uint8_t val)
     #endif
   #endif
 
-  pinMode(pin, OUTPUT);
+  // Set pin to output
+  DDRB |= _BV(pin);
 
   // Handle off condition
   if(val == 0)
diff --git a/avr/cores/microcore/wiring_shift.c b/avr/cores/microcore/wiring_shift.c
index 0c8c01dc..5cef5c45 100644
--- a/avr/cores/microcore/wiring_shift.c
+++ b/avr/cores/microcore/wiring_shift.c
@@ -13,33 +13,23 @@ functions shiftIn() and shiftOut().
 
 uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder)
 {
-  check_valid_digital_pin(dataPin);
-  check_valid_digital_pin(clockPin);
-
-  #if defined(SAFEMODE)
-    if(clockPin < 2)
-      turnOffPWM(clockPin); // If it's a PWM pin, make sure PWM is off
-    if(dataPin < 2)
-      turnOffPWM(dataPin);  // If it's a PWM pin, make sure PWM is off
-  #endif
-
   uint8_t value = 0;
   uint8_t i = 8;
   do
   {
-    digitalWrite(clockPin, HIGH);
+    PORTB |= _BV(clockPin);
     if(bitOrder == MSBFIRST)
       value <<= 1;
     else
       value >>= 1;
-    if(digitalRead(dataPin))
+    if(PINB & _BV(dataPin))
     {
       if(bitOrder == MSBFIRST)
         value |= 0x01;
       else
         value |= 0x80;
     }
-    digitalWrite(clockPin, LOW);
+    PORTB &= ~_BV(clockPin);
   }
   while(--i);
 
@@ -49,21 +39,11 @@ uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder)
 
 void shiftOut(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder, uint8_t value)
 {
-  check_valid_digital_pin(dataPin);
-  check_valid_digital_pin(clockPin);
-
   const uint8_t datapinMask = _BV(dataPin);
   const uint8_t clkpinMask = _BV(clockPin);
   uint8_t i = 8;
   uint8_t portbits = (PORTB &= ~(datapinMask | clkpinMask));
 
-  #if defined(SAFEMODE)
-    if(clockPin < 2)
-      turnOffPWM(clockPin); // If it's a PWM pin, make sure PWM is off
-    if(dataPin < 2)
-      turnOffPWM(dataPin);  // If it's a PWM pin, make sure PWM is off
-  #endif
-
   do
   {
     if(bitOrder == MSBFIRST)