diff --git a/sonoff/_changelog.ino b/sonoff/_changelog.ino
index 23bbe3dc2..f664eb7a6 100644
--- a/sonoff/_changelog.ino
+++ b/sonoff/_changelog.ino
@@ -1,6 +1,6 @@
 /* 6.3.0.7 20181111
  * Fix wifi connection errors using wifi disconnect and ESP.reset instead of ESP.restart
- * Fix Sonoff Pow R2 and Sonoff S31 Serial interface hang caused by MP3 driver
+ * Fix Sonoff Pow R2 and Sonoff S31 Serial interface hang caused by Sonoff Basic R2 driver delay implementation (and possibly core bug)
  *
  * 6.3.0.6 20181110
  * Change GUI Configure Module by using AJAX for data fetch to cut page size (and memory use) by 40%
diff --git a/sonoff/support.ino b/sonoff/support.ino
index 9389714ec..0c5203d69 100644
--- a/sonoff/support.ino
+++ b/sonoff/support.ino
@@ -765,6 +765,15 @@ uint8_t ValidGPIO(uint8_t pin, uint8_t gpio)
   return result;
 }
 
+void AppDelay()
+{
+  if (APP_BAUDRATE == baudrate) {  // When baudrate too low it will fail on Sonoff Pow R2 and S31 serial interface initialization
+    if (global_state.wifi_down) {
+      delay(DRIVER_BOOT_DELAY);
+    }
+  }
+}
+
 /*********************************************************************************************\
  * Sleep aware time scheduler functions borrowed from ESPEasy
 \*********************************************************************************************/
diff --git a/sonoff/xdrv_interface.ino b/sonoff/xdrv_interface.ino
index 0f0171e20..cb3a69c22 100644
--- a/sonoff/xdrv_interface.ino
+++ b/sonoff/xdrv_interface.ino
@@ -238,7 +238,7 @@ boolean XdrvCall(byte Function)
   boolean result = false;
 
   for (byte x = 0; x < xdrv_present; x++) {
-    if (global_state.wifi_down) { delay(DRIVER_BOOT_DELAY); }
+    AppDelay();
     result = xdrv_func_ptr[x](Function);
     if (result) break;
   }
diff --git a/sonoff/xsns_interface.ino b/sonoff/xsns_interface.ino
index a3cf4d772..723e8f070 100644
--- a/sonoff/xsns_interface.ino
+++ b/sonoff/xsns_interface.ino
@@ -568,7 +568,7 @@ boolean XsnsNextCall(byte Function)
     xsns_index++;
     if (xsns_index == xsns_present) { xsns_index = 0; }
   }
-  if (global_state.wifi_down) { delay(DRIVER_BOOT_DELAY); }
+  AppDelay();
   return xsns_func_ptr[xsns_index](Function);
 }
 
@@ -586,7 +586,7 @@ boolean XsnsCall(byte Function)
 #ifdef PROFILE_XSNS_SENSOR_EVERY_SECOND
       uint32_t profile_start_millis = millis();
 #endif  // PROFILE_XSNS_SENSOR_EVERY_SECOND
-      if (global_state.wifi_down) { delay(DRIVER_BOOT_DELAY); }
+      AppDelay();
       result = xsns_func_ptr[x](Function);
 
 #ifdef PROFILE_XSNS_SENSOR_EVERY_SECOND