diff --git a/cores/arduino/Arduino.h b/cores/arduino/Arduino.h
index ac775f1..16dd759 100644
--- a/cores/arduino/Arduino.h
+++ b/cores/arduino/Arduino.h
@@ -114,7 +114,7 @@ typedef unsigned int word;
 
 #define bit(b) (1UL << (b))
 
-typedef uint8_t boolean;
+typedef bool boolean;
 typedef uint8_t byte;
 
 void init(void);