diff --git a/hardware/arduino/cores/arduino/Arduino.h b/hardware/arduino/cores/arduino/Arduino.h
index 830c9952f..d592aab95 100755
--- a/hardware/arduino/cores/arduino/Arduino.h
+++ b/hardware/arduino/cores/arduino/Arduino.h
@@ -11,6 +11,71 @@
 
 #include "binary.h"
 
+// Workaround for wrong definitions in "iom32u4.h".
+// This should be fixed in the AVR toolchain.
+#ifdef __AVR_ATmega32U4__
+#undef UHCON
+#undef UHINT
+#undef UHIEN
+#undef UHADDR
+#undef UHFNUM
+#undef UHFNUML
+#undef UHFNUMH
+#undef UHFLEN
+#undef UPINRQX
+#undef UPINTX
+#undef UPNUM
+#undef UPRST
+#undef UPCONX
+#undef UPCFG0X
+#undef UPCFG1X
+#undef UPSTAX
+#undef UPCFG2X
+#undef UPIENX
+#undef UPDATX
+#undef TCCR2A
+#undef WGM20
+#undef WGM21
+#undef COM2B0
+#undef COM2B1
+#undef COM2A0
+#undef COM2A1
+#undef TCCR2B
+#undef CS20
+#undef CS21
+#undef CS22
+#undef WGM22
+#undef FOC2B
+#undef FOC2A
+#undef TCNT2
+#undef TCNT2_0
+#undef TCNT2_1
+#undef TCNT2_2
+#undef TCNT2_3
+#undef TCNT2_4
+#undef TCNT2_5
+#undef TCNT2_6
+#undef TCNT2_7
+#undef OCR2A
+#undef OCR2_0
+#undef OCR2_1
+#undef OCR2_2
+#undef OCR2_3
+#undef OCR2_4
+#undef OCR2_5
+#undef OCR2_6
+#undef OCR2_7
+#undef OCR2B
+#undef OCR2_0
+#undef OCR2_1
+#undef OCR2_2
+#undef OCR2_3
+#undef OCR2_4
+#undef OCR2_5
+#undef OCR2_6
+#undef OCR2_7
+#endif
+
 #ifdef __cplusplus
 extern "C"{
 #endif
diff --git a/hardware/arduino/cores/arduino/Tone.cpp b/hardware/arduino/cores/arduino/Tone.cpp
index 20eed3f48..9bb6fe721 100755
--- a/hardware/arduino/cores/arduino/Tone.cpp
+++ b/hardware/arduino/cores/arduino/Tone.cpp
@@ -29,6 +29,7 @@ Version Modified By Date     Comments
                     09/11/25 Fixed timer0 from being excluded
 0006    D Mellis    09/12/29 Replaced objects with functions
 0007    M Sproul    10/08/29 Changed #ifdefs from cpu to register
+0008    S Kanemoto  12/06/22 Fixed for Leonardo by @maris_HY
 *************************************************/
 
 #include <avr/interrupt.h>
@@ -85,10 +86,10 @@ volatile uint8_t timer5_pin_mask;
 #endif
 
 
-// MLS: This does not make sense, the 3 options are the same
 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
 
 #define AVAILABLE_TONE_PINS 1
+#define USE_TIMER2
 
 const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 3, 4, 5, 1, 0 */ };
 static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255, 255, 255, 255, 255 */ };
@@ -96,13 +97,23 @@ static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255, 255, 255, 255, 25
 #elif defined(__AVR_ATmega8__)
 
 #define AVAILABLE_TONE_PINS 1
+#define USE_TIMER2
 
 const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 1 */ };
 static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255 */ };
 
+#elif defined(__AVR_ATmega32U4__)
+ 
+#define AVAILABLE_TONE_PINS 1
+#define USE_TIMER3
+ 
+const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 3 /*, 1 */ };
+static uint8_t tone_pins[AVAILABLE_TONE_PINS] = { 255 /*, 255 */ };
+ 
 #else
 
 #define AVAILABLE_TONE_PINS 1
+#define USE_TIMER2
 
 // Leave timer 0 to last.
 const uint8_t PROGMEM tone_pin_to_timer_PGM[] = { 2 /*, 1, 0 */ };
@@ -480,8 +491,7 @@ void noTone(uint8_t _pin)
   digitalWrite(_pin, 0);
 }
 
-#if 0
-#if !defined(__AVR_ATmega8__)
+#ifdef USE_TIMER0
 ISR(TIMER0_COMPA_vect)
 {
   if (timer0_toggle_count != 0)
@@ -501,6 +511,7 @@ ISR(TIMER0_COMPA_vect)
 #endif
 
 
+#ifdef USE_TIMER1
 ISR(TIMER1_COMPA_vect)
 {
   if (timer1_toggle_count != 0)
@@ -520,6 +531,7 @@ ISR(TIMER1_COMPA_vect)
 #endif
 
 
+#ifdef USE_TIMER2
 ISR(TIMER2_COMPA_vect)
 {
 
@@ -541,12 +553,10 @@ ISR(TIMER2_COMPA_vect)
 //    *timer2_pin_port &= ~(timer2_pin_mask);  // keep pin low after stop
   }
 }
+#endif
 
 
-
-//#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
-#if 0
-
+#ifdef USE_TIMER3
 ISR(TIMER3_COMPA_vect)
 {
   if (timer3_toggle_count != 0)
@@ -563,7 +573,10 @@ ISR(TIMER3_COMPA_vect)
     *timer3_pin_port &= ~(timer3_pin_mask);  // keep pin low after stop
   }
 }
+#endif
 
+
+#ifdef USE_TIMER4
 ISR(TIMER4_COMPA_vect)
 {
   if (timer4_toggle_count != 0)
@@ -580,7 +593,10 @@ ISR(TIMER4_COMPA_vect)
     *timer4_pin_port &= ~(timer4_pin_mask);  // keep pin low after stop
   }
 }
+#endif
 
+
+#ifdef USE_TIMER5
 ISR(TIMER5_COMPA_vect)
 {
   if (timer5_toggle_count != 0)
@@ -597,5 +613,4 @@ ISR(TIMER5_COMPA_vect)
     *timer5_pin_port &= ~(timer5_pin_mask);  // keep pin low after stop
   }
 }
-
 #endif
diff --git a/libraries/Servo/Servo.h b/libraries/Servo/Servo.h
index bf3e01215..8168494c3 100755
--- a/libraries/Servo/Servo.h
+++ b/libraries/Servo/Servo.h
@@ -65,9 +65,8 @@
 typedef enum { _timer5, _timer1, _timer3, _timer4, _Nbr_16timers } timer16_Sequence_t ;
 
 #elif defined(__AVR_ATmega32U4__)  
-#define _useTimer3
 #define _useTimer1 
-typedef enum { _timer3, _timer1, _Nbr_16timers } timer16_Sequence_t ;
+typedef enum { _timer1, _Nbr_16timers } timer16_Sequence_t ;
 
 #elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
 #define _useTimer3
@@ -124,4 +123,4 @@ private:
    int8_t max;                       // maximum is this value times 4 added to MAX_PULSE_WIDTH   
 };
 
-#endif
\ No newline at end of file
+#endif