diff --git a/RFM69_OTA.cpp b/RFM69_OTA.cpp
index de268ec..e09a01f 100644
--- a/RFM69_OTA.cpp
+++ b/RFM69_OTA.cpp
@@ -30,7 +30,7 @@
 // Please maintain this license information along with authorship
 // and copyright notices in any redistribution of this code
 // **********************************************************************************
-#ifndef __arm__
+#ifdef __AVR__
 #include <RFM69_OTA.h>
 #include <RFM69registers.h>
 #include <avr/wdt.h>
@@ -518,4 +518,4 @@ void resetUsingWatchdog(uint8_t DEBUG)
   wdt_enable(WDTO_15MS);
   while(1) if (DEBUG) Serial.print(F("."));
 }
-#endif
\ No newline at end of file
+#endif // __AVR__
diff --git a/RFM69_OTA.h b/RFM69_OTA.h
index 012f43e..3f38060 100644
--- a/RFM69_OTA.h
+++ b/RFM69_OTA.h
@@ -30,7 +30,7 @@
 // Please maintain this license information along with authorship
 // and copyright notices in any redistribution of this code
 // **********************************************************************************
-#ifndef __arm__
+#ifdef __AVR__
 
 #ifndef RFM69_OTA_H
 #define RFM69_OTA_H
@@ -78,5 +78,5 @@ uint8_t BYTEfromHEX(char MSB, char LSB);
 uint8_t readSerialLine(char* input, char endOfLineChar=10, uint8_t maxLength=115, uint16_t timeout=1000);
 void PrintHex83(uint8_t* data, uint8_t length);
 
-#endif
-#endif
\ No newline at end of file
+#endif // RFM69_OTA_H
+#endif // __AVR__