diff --git a/settings.h b/settings.h
index 6b134dfb..275f0a6b 100644
--- a/settings.h
+++ b/settings.h
@@ -173,6 +173,7 @@ e-mail   :  support@circuitsathome.com
 #ifdef STM32F4
 #include "stm32f4xx_hal.h"
 extern SPI_HandleTypeDef SPI_Handle; // Needed to be declared in your main.cpp
+#define MFK_CASTUINT8T (uint8_t)
 #endif
 
 // Fix defines on Arduino Due