diff --git a/hardware/arduino/cores/arduino/WString.cpp b/hardware/arduino/cores/arduino/WString.cpp
index ed880ce2b90..6299c94e22c 100644
--- a/hardware/arduino/cores/arduino/WString.cpp
+++ b/hardware/arduino/cores/arduino/WString.cpp
@@ -453,6 +453,21 @@ unsigned char String::equals(const char *cstr) const
 	return strcmp(buffer, cstr) == 0;
 }
 
+unsigned char String::equals(const __FlashStringHelper *fstr) const
+{
+	const char PROGMEM *p = (const char PROGMEM *)fstr;
+	
+	for (int i = 0; i < len; i++)
+	{
+		if (pgm_read_byte(p) == 0) return 0;
+		if (buffer[i] != (char)pgm_read_byte(p++)) return 0;
+	}
+	
+	if (pgm_read_byte(p) != 0) return 0;
+	
+	return 1;
+}
+
 unsigned char String::operator<(const String &rhs) const
 {
 	return compareTo(rhs) < 0;
diff --git a/hardware/arduino/cores/arduino/WString.h b/hardware/arduino/cores/arduino/WString.h
index 74024309278..4da29a13a45 100644
--- a/hardware/arduino/cores/arduino/WString.h
+++ b/hardware/arduino/cores/arduino/WString.h
@@ -139,10 +139,13 @@ class String
 	int compareTo(const String &s) const;
 	unsigned char equals(const String &s) const;
 	unsigned char equals(const char *cstr) const;
+	unsigned char equals(const __FlashStringHelper *fstr) const;
 	unsigned char operator == (const String &rhs) const {return equals(rhs);}
 	unsigned char operator == (const char *cstr) const {return equals(cstr);}
+	unsigned char operator == (const __FlashStringHelper *fstr) const {return equals(fstr);}
 	unsigned char operator != (const String &rhs) const {return !equals(rhs);}
 	unsigned char operator != (const char *cstr) const {return !equals(cstr);}
+	unsigned char operator != (const __FlashStringHelper *fstr) const {return !equals(fstr);}
 	unsigned char operator <  (const String &rhs) const;
 	unsigned char operator >  (const String &rhs) const;
 	unsigned char operator <= (const String &rhs) const;