diff --git a/src/esp8266/RBDmcuESP8266.cpp b/src/esp8266/RBDmcuESP8266.cpp
index 0cb1f40..ed9ad59 100644
--- a/src/esp8266/RBDmcuESP8266.cpp
+++ b/src/esp8266/RBDmcuESP8266.cpp
@@ -136,7 +136,7 @@ void dimmerLamp::toggleSettings(int minValue, int maxValue)
 	toggleReload = 50;
 }
  
-void isr_ext()
+void ICACHE_RAM_ATTR isr_ext()
 {
 	for (int i = 0; i < current_dim; i++ ) 
 		if (dimState[i] == ON) 
@@ -200,4 +200,4 @@ void ICACHE_RAM_ATTR onTimerISR()
 	
 }
 
-#endif
\ No newline at end of file
+#endif