diff --git a/variants/ET-Board/pins_arduino.h b/variants/ET-Board/pins_arduino.h
index 617c2011..8ab4a0b6 100644
--- a/variants/ET-Board/pins_arduino.h
+++ b/variants/ET-Board/pins_arduino.h
@@ -11,6 +11,12 @@
 #define digitalPinToInterrupt(p)    (((p)<40)?(p):-1)
 #define digitalPinHasPWM(p)         (p < 34)
 
+static const uint8_t LED_BUILTIN = 5;
+#define BUILTIN_LED  LED_BUILTIN // backward compatibility
+#define LED_BUILTIN LED_BUILTIN
+
+
+
 static const uint8_t TX = 34;
 static const uint8_t RX = 35;