diff --git a/hardware/arduino/cores/arduino/HardwareSerial.cpp b/hardware/arduino/cores/arduino/HardwareSerial.cpp
index 2e64acb8248..38500d87789 100644
--- a/hardware/arduino/cores/arduino/HardwareSerial.cpp
+++ b/hardware/arduino/cores/arduino/HardwareSerial.cpp
@@ -89,7 +89,7 @@ inline void store_char(unsigned char c, ring_buffer *buffer)
 #if !defined(USART0_RX_vect) && defined(USART1_RX_vect)
 // do nothing - on the 32u4 the first USART is USART1
 #else
-#if !defined(USART_RX_vect) && !defined(SIG_USART0_RECV) && \
+#if !defined(USART_RX_vect) && /*!defined(SIG_USART0_RECV) &&*/ \
     !defined(SIG_UART0_RECV) && !defined(USART0_RX_vect) && \
 	!defined(SIG_UART_RECV)
   #error "Don't know what the Data Received vector is called for the first UART"
@@ -99,8 +99,8 @@ inline void store_char(unsigned char c, ring_buffer *buffer)
   #define serialEvent_implemented
 #if defined(USART_RX_vect)
   SIGNAL(USART_RX_vect)
-#elif defined(SIG_USART0_RECV)
-  SIGNAL(SIG_USART0_RECV)
+//#elif defined(SIG_USART0_RECV)
+//  SIGNAL(SIG_USART0_RECV)
 #elif defined(SIG_UART0_RECV)
   SIGNAL(SIG_UART0_RECV)
 #elif defined(USART0_RX_vect)
@@ -143,8 +143,8 @@ inline void store_char(unsigned char c, ring_buffer *buffer)
       unsigned char c = UDR1;
     };
   }
-#elif defined(SIG_USART1_RECV)
-  #error SIG_USART1_RECV
+//#elif defined(SIG_USART1_RECV)
+//  #error SIG_USART1_RECV
 #endif
 
 #if defined(USART2_RX_vect) && defined(UDR2)
@@ -160,8 +160,8 @@ inline void store_char(unsigned char c, ring_buffer *buffer)
       unsigned char c = UDR2;
     };
   }
-#elif defined(SIG_USART2_RECV)
-  #error SIG_USART2_RECV
+//#elif defined(SIG_USART2_RECV)
+//  #error SIG_USART2_RECV
 #endif
 
 #if defined(USART3_RX_vect) && defined(UDR3)
@@ -177,8 +177,8 @@ inline void store_char(unsigned char c, ring_buffer *buffer)
       unsigned char c = UDR3;
     };
   }
-#elif defined(SIG_USART3_RECV)
-  #error SIG_USART3_RECV
+//#elif defined(SIG_USART3_RECV)
+//  #error SIG_USART3_RECV
 #endif
 
 void serialEventRun(void)