diff --git a/demos/ARMCM4-STM32F407-DISCOVERY/chconf.h b/demos/ARMCM4-STM32F407-DISCOVERY/chconf.h
index cc866e3cc..32d3b36a8 100644
--- a/demos/ARMCM4-STM32F407-DISCOVERY/chconf.h
+++ b/demos/ARMCM4-STM32F407-DISCOVERY/chconf.h
@@ -537,6 +537,10 @@
 /* Port-specific settings (override port settings defaulted in chcore.h).    */
 /*===========================================================================*/
 
+/* NOTE: When changing this option you also have to enable or disable the FPU
+   in the project options.*/
+#define CORTEX_USE_FPU                  FALSE
+
 #endif  /* _CHCONF_H_ */
 
 /** @} */