diff --git a/sonoff/_changelog.ino b/sonoff/_changelog.ino
index 4811e0073..f29d95cb8 100644
--- a/sonoff/_changelog.ino
+++ b/sonoff/_changelog.ino
@@ -3,6 +3,7 @@
  * Change pubsubclient MQTT_KEEPALIVE from 10 to 30 seconds in preparation of AWS IoT support
  * Add support for AWS IoT with TLS 1.2 on core 2.5.2. Full doc here: https://github.com/arendst/Sonoff-Tasmota/wiki/AWS-IoT
  * Add some MQTT housekeeping which might solve issue (#5755)
+ * Add command SetOption65 0/1 and more Tuya Serial based device support (#5815)
  *
  * 6.5.0.14 20190602
  * Change webserver HTML input, button, textarea, and select name based on id
diff --git a/sonoff/settings.h b/sonoff/settings.h
index fcb58a174..0fa7f5d48 100644
--- a/sonoff/settings.h
+++ b/sonoff/settings.h
@@ -78,7 +78,7 @@ typedef union {                            // Restricted by MISRA-C Rule 18.4 bu
     uint32_t no_hold_retain : 1;           // bit 12 (v6.4.1.19) - SetOption62 - Don't use retain flag on HOLD messages
     uint32_t no_power_feedback : 1;        // bit 13 (v6.5.0.9)  - SetOption63 - Don't scan relay power state at restart
     uint32_t use_underscore : 1;           // bit 14 (v6.5.0.12) - SetOption64 - Enable "_" instead of "-" as sensor index separator
-    uint32_t tuya_show_dimmer : 1;		     // bit 15 (v6.5.0.12) - SetOption65 - Enable or Disable Dimmer slider control 
+    uint32_t tuya_show_dimmer : 1;		     // bit 15 (v6.5.0.15) - SetOption65 - Enable or Disable Dimmer slider control
     uint32_t spare16 : 1;
     uint32_t spare17 : 1;
     uint32_t spare18 : 1;
diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index 614d9fd8f..da0c83db1 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -109,7 +109,6 @@ unsigned long pulse_timer[MAX_PULSETIMERS] = { 0 }; // Power off timer
 unsigned long blink_timer = 0;              // Power cycle timer
 unsigned long backlog_delay = 0;            // Command backlog delay
 power_t power = 0;                          // Current copy of Settings.power
-power_t deviceid = 1;                       // hold current deviceid
 power_t blink_power;                        // Blink power state
 power_t blink_mask = 0;                     // Blink relay active mask
 power_t blink_powersave;                    // Blink start power save state
@@ -143,6 +142,7 @@ uint8_t backlog_pointer = 0;                // Command backlog pointer
 uint8_t sleep;                              // Current copy of Settings.sleep
 uint8_t blinkspeed = 1;                     // LED blink rate
 uint8_t pin[GPIO_MAX];                      // Possible pin configurations
+uint8_t active_device = 1;                  // Active device in ExecuteCommandPower
 uint8_t leds_present = 0;                   // Max number of LED supported
 uint8_t led_inverted = 0;                   // LED inverted flag (1 = (0 = On, 1 = Off))
 uint8_t led_power = 0;                      // LED power state
@@ -1653,8 +1653,6 @@ void ExecuteCommandPower(uint8_t device, uint8_t state, int source)
 
 //  ShowSource(source);
 
-  deviceid = device;
-
   if (SONOFF_IFAN02 == my_module_type) {
     blink_mask &= 1;                 // No blinking on the fan relays
     Settings.flag.interlock = 0;     // No interlock mode as it is already done by the microcontroller
@@ -1668,7 +1666,10 @@ void ExecuteCommandPower(uint8_t device, uint8_t state, int source)
     state &= 1;
     publish_power = 0;
   }
+
   if ((device < 1) || (device > devices_present)) device = 1;
+  active_device = device;
+
   if (device <= MAX_PULSETIMERS) { SetPulseTimer(device -1, 0); }
   power_t mask = 1 << (device -1);        // Device to control
   if (state <= POWER_TOGGLE) {
diff --git a/sonoff/xdrv_01_webserver.ino b/sonoff/xdrv_01_webserver.ino
index cde0feb28..939ab5b7c 100644
--- a/sonoff/xdrv_01_webserver.ino
+++ b/sonoff/xdrv_01_webserver.ino
@@ -922,8 +922,7 @@ void HandleRoot(void)
       if ((LST_COLDWARM == (light_type &7)) || (LST_RGBWC == (light_type &7))) {
         WSContentSend_P(HTTP_MSG_SLIDER1, LightGetColorTemp());
       }
-      if(Settings.flag3.tuya_show_dimmer == 0)
-      {
+      if (!Settings.flag3.tuya_show_dimmer) {
         WSContentSend_P(HTTP_MSG_SLIDER2, Settings.light_dimmer);
       }
     }
diff --git a/sonoff/xdrv_16_tuyadimmer.ino b/sonoff/xdrv_16_tuyadimmer.ino
index 667d0d458..286d901fe 100644
--- a/sonoff/xdrv_16_tuyadimmer.ino
+++ b/sonoff/xdrv_16_tuyadimmer.ino
@@ -123,7 +123,7 @@ bool TuyaSetPower(void)
   int16_t source = XdrvMailbox.payload;
 
   if (source != SRC_SWITCH && TuyaSerial) {  // ignore to prevent loop from pushing state from faceplate interaction
-    TuyaSendBool(deviceid, bitRead(rpower, deviceid-1));
+    TuyaSendBool(active_device, bitRead(rpower, active_device-1));
     status = true;
   }
   return status;
@@ -207,7 +207,7 @@ void TuyaPacketProcess(void)
       else if (tuya_buffer[5] == 8) {  // dim packet
 
         AddLog_P2(LOG_LEVEL_DEBUG, PSTR("TYA: RX Dim State=%d"), tuya_buffer[13]);
-        if(Settings.flag3.tuya_show_dimmer == 0) // 
+        if(Settings.flag3.tuya_show_dimmer == 0) //
         {
           if (!Settings.param[P_TUYA_DIMMER_ID]) {
             AddLog_P2(LOG_LEVEL_DEBUG, PSTR("TYA: Autoconfiguring Dimmer ID %d"), tuya_buffer[6]);