diff --git a/radio/src/gui/128x64/gui.h b/radio/src/gui/128x64/gui.h
index f557fba48..0a60539ca 100644
--- a/radio/src/gui/128x64/gui.h
+++ b/radio/src/gui/128x64/gui.h
@@ -111,7 +111,7 @@ extern const CheckIncDecStops &stopsSwitch;
   const CheckIncDecStops &var  = (const CheckIncDecStops&)_ ## var;
 #define CATEGORY_END(val)                                          \
   (val), (val+1)
-int checkIncDec(event_t event, int val, int i_min, int i_max, unsigned int i_flags=0, IsValueAvailable isValueAvailable=NULL, const CheckIncDecStops &stops=stops100);
+int checkIncDec(event_t event, int val, int i_min, int i_max, unsigned int i_flags=0, IsValueAvailable isValueAvailable=nullptr, const CheckIncDecStops &stops=stops100);
 
 #define checkIncDecModel(event, i_val, i_min, i_max) checkIncDec(event, i_val, i_min, i_max, EE_MODEL)
 #define checkIncDecModelZero(event, i_val, i_max) checkIncDec(event, i_val, 0, i_max, EE_MODEL)