diff --git a/sonoff/xsns_21_sgp30.ino b/sonoff/xsns_21_sgp30.ino
index 16c4657ad..53b9a27db 100644
--- a/sonoff/xsns_21_sgp30.ino
+++ b/sonoff/xsns_21_sgp30.ino
@@ -149,7 +149,7 @@ void Sgp30Show(bool json)
  * Interface
 \*********************************************************************************************/
 
-bool Xsns21(byte function)
+bool Xsns21(uint8_t function)
 {
   bool result = false;