diff --git a/sonoff/xdrv_06_snfbridge.ino b/sonoff/xdrv_06_snfbridge.ino
index db786d3b5..c7b57c0c1 100644
--- a/sonoff/xdrv_06_snfbridge.ino
+++ b/sonoff/xdrv_06_snfbridge.ino
@@ -424,7 +424,7 @@ void SonoffBridgeLearn(uint8_t key)
  * Commands
 \*********************************************************************************************/
 
-void CmndRfBridge()  // RfSync, RfLow, RfHigh, RfHost and RfCode
+void CmndRfBridge(void)  // RfSync, RfLow, RfHigh, RfHost and RfCode
 {
   char *p;
   char stemp [10];
diff --git a/sonoff/xdrv_24_buzzer.ino b/sonoff/xdrv_24_buzzer.ino
index 8646c099c..2913b6cb6 100644
--- a/sonoff/xdrv_24_buzzer.ino
+++ b/sonoff/xdrv_24_buzzer.ino
@@ -79,7 +79,7 @@ void BuzzerEnabledBeep(uint32_t count)
 
 /*********************************************************************************************/
 
-bool BuzzerPinState()
+bool BuzzerPinState(void)
 {
   if (XdrvMailbox.index == GPIO_BUZZER_INV) {
     Buzzer.inverted = 1;
diff --git a/sonoff/xsns_01_counter.ino b/sonoff/xsns_01_counter.ino
index eaac77282..a6bc80acb 100644
--- a/sonoff/xsns_01_counter.ino
+++ b/sonoff/xsns_01_counter.ino
@@ -82,7 +82,7 @@ void CounterUpdate4(void)
 
 /********************************************************************************************/
 
-bool CounterPinState()
+bool CounterPinState(void)
 {
   if ((XdrvMailbox.index >= GPIO_CNTR1_NP) && (XdrvMailbox.index < (GPIO_CNTR1_NP + MAX_COUNTERS))) {
     bitSet(counter_no_pullup, XdrvMailbox.index - GPIO_CNTR1_NP);