diff --git a/cores/arduino/Arduino.h b/cores/arduino/Arduino.h
index 93a3525..425dfcb 100755
--- a/cores/arduino/Arduino.h
+++ b/cores/arduino/Arduino.h
@@ -113,6 +113,7 @@ typedef uint8_t boolean;
 typedef uint8_t byte;
 
 void init(void);
+void initVariant(void);
 
 void pinMode(uint8_t, uint8_t);
 void digitalWrite(uint8_t, uint8_t);
diff --git a/cores/arduino/main.cpp b/cores/arduino/main.cpp
index 0ad6962..091c365 100644
--- a/cores/arduino/main.cpp
+++ b/cores/arduino/main.cpp
@@ -19,10 +19,17 @@
 
 #include <Arduino.h>
 
+// Weak empty variant initialization function.
+// May be redefined by variant files.
+void initVariant() __attribute__((weak));
+void initVariant() { }
+
 int main(void)
 {
 	init();
 
+	initVariant();
+
 #if defined(USBCON)
 	USBDevice.attach();
 #endif