diff --git a/sonoff/xsns_26_lm75ad.ino b/sonoff/xsns_26_lm75ad.ino
index 092c8d153..1fd0f4448 100644
--- a/sonoff/xsns_26_lm75ad.ino
+++ b/sonoff/xsns_26_lm75ad.ino
@@ -46,7 +46,7 @@ uint8_t lm75ad_type = 0;
 uint8_t lm75ad_address;
 uint8_t lm75ad_addresses[] = { LM75AD_ADDRESS1, LM75AD_ADDRESS2, LM75AD_ADDRESS3, LM75AD_ADDRESS4, LM75AD_ADDRESS5, LM75AD_ADDRESS6, LM75AD_ADDRESS7, LM75AD_ADDRESS8 };
 
-void LM75ADDetect()
+void LM75ADDetect(void)
 {
   if (lm75ad_type) { return; }
 
@@ -64,7 +64,7 @@ void LM75ADDetect()
   }
 }
 
-float LM75ADGetTemp() {
+float LM75ADGetTemp(void) {
   int16_t sign = 1;
 
   uint16_t t = I2cRead16(lm75ad_address, LM75_TEMP_REGISTER);
diff --git a/sonoff/xsns_29_mcp230xx.ino b/sonoff/xsns_29_mcp230xx.ino
index 50798eb8f..1ca59f8ed 100644
--- a/sonoff/xsns_29_mcp230xx.ino
+++ b/sonoff/xsns_29_mcp230xx.ino
@@ -181,7 +181,7 @@ void MCP230xx_ApplySettings(void) {
   MCP230xx_CheckForIntCounter(); // update register on whether or not we should be counting interrupts
 }
 
-void MCP230xx_Detect()
+void MCP230xx_Detect(void)
 {
   if (mcp230xx_type) {
     return;