diff --git a/FanController.cpp b/FanController.cpp
index ef3dade..2797fed 100644
--- a/FanController.cpp
+++ b/FanController.cpp
@@ -5,6 +5,12 @@
 	#include <analogWrite.h>
 #endif
 
+#if defined(ESP8266)
+	#define ISR_PREFIX ICACHE_RAM_ATTR
+#else
+	#define ISR_PREFIX
+#endif
+
 FanController::FanController(byte sensorPin, unsigned int sensorThreshold, byte pwmPin)
 {
 	_sensorPin = sensorPin;
@@ -40,8 +46,8 @@ unsigned int FanController::getSpeed() {
 		_halfRevs = 0;
 		_lastMillis = millis();
 		_attachInterrupt();
-		return _lastReading;
 	}
+	return _lastReading;
 }
 
 void FanController::setDutyCycle(byte dutyCycle) {
@@ -93,9 +99,9 @@ void FanController::_triggerCaller(byte instance)
 	}
 }
 
-void FanController::_triggerExt0() { FanController::_triggerCaller(0); }
-void FanController::_triggerExt1() { FanController::_triggerCaller(1); }
-void FanController::_triggerExt2() { FanController::_triggerCaller(2); }
-void FanController::_triggerExt3() { FanController::_triggerCaller(3); }
-void FanController::_triggerExt4() { FanController::_triggerCaller(4); }
-void FanController::_triggerExt5() { FanController::_triggerCaller(5); }
\ No newline at end of file
+ISR_PREFIX void FanController::_triggerExt0() { FanController::_triggerCaller(0); }
+ISR_PREFIX void FanController::_triggerExt1() { FanController::_triggerCaller(1); }
+ISR_PREFIX void FanController::_triggerExt2() { FanController::_triggerCaller(2); }
+ISR_PREFIX void FanController::_triggerExt3() { FanController::_triggerCaller(3); }
+ISR_PREFIX void FanController::_triggerExt4() { FanController::_triggerCaller(4); }
+ISR_PREFIX void FanController::_triggerExt5() { FanController::_triggerCaller(5); }
\ No newline at end of file
diff --git a/FanController.h b/FanController.h
index 6d7c7c5..44dc3e3 100644
--- a/FanController.h
+++ b/FanController.h
@@ -20,7 +20,7 @@ class FanController
 		static FanController *_instances[6];
 		byte _sensorPin;
 		byte _sensorInterruptPin;
-		byte _sensorThreshold;
+		unsigned int _sensorThreshold;
 		byte _pwmPin;
 		byte _pwmDutyCycle;
 		byte _instance;
diff --git a/library.json b/library.json
index 136301f..2a42b3e 100644
--- a/library.json
+++ b/library.json
@@ -15,7 +15,7 @@
       "maintainer": true
     }
   ],
-  "version": "1.0.5",
+  "version": "1.0.6",
   "frameworks": "arduino",
   "platforms": "*"
 }
diff --git a/library.properties b/library.properties
index 9155170..78db404 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=FanController
-version=1.0.5
+version=1.0.6
 author=Giorgio Aresu <giorgioaresu@gmail.com>
 maintainer=Giorgio Aresu <giorgioaresu@gmail.com>
 sentence=Arduino Library for controlling PC fans