From 74099b54e32cc1fa50fbd374d1990e33dbf0d4be Mon Sep 17 00:00:00 2001
From: Theo Arends <11044339+arendst@users.noreply.github.com>
Date: Mon, 30 Mar 2026 14:38:20 +0200
Subject: [PATCH] Fix Shelly Dimmer 2 serial timeout regression from v15.2.0.1
 (#24560)

---
 CHANGELOG.md                                          | 1 +
 RELEASENOTES.md                                       | 1 +
 tasmota/tasmota_xdrv_driver/xdrv_45_shelly_dimmer.ino | 2 +-
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4b10acc90..d4feeaa63 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@ All notable changes to this project will be documented in this file.
 - Athom esp32 2-3-4 gang change led behaviour after firmware update (#24509)
 - ESP8266 heap drain and exception 29 when DHCP provides NTP server (#24515, #24566)
 - NeoPool possible IntegerDivideByZero (#24578)
+- Shelly Dimmer 2 serial timeout regression from v15.2.0.1 (#24560)
 
 ### Removed
 
diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index f5da3fde1..9a1f66c1e 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -148,6 +148,7 @@ The latter links can be used for OTA upgrades too like ``OtaUrl https://ota.tasm
 - ESP8266 heap drain and exception 29 when DHCP provides NTP server [#24515](https://github.com/arendst/Tasmota/issues/24515), [#24566](https://github.com/arendst/Tasmota/issues/24566)
 - Crash when shutting down Wifi with `Wifi 0` [#24536](https://github.com/arendst/Tasmota/issues/24536)
 - Don't send extraneous `0\r\n\r\n` with non-chunked HTTP/1.0 [#24518](https://github.com/arendst/Tasmota/issues/24518)
+- Shelly Dimmer 2 serial timeout regression from v15.2.0.1 [#24560](https://github.com/arendst/Tasmota/issues/24560)
 - NeoPool possible IntegerDivideByZero [#24578](https://github.com/arendst/Tasmota/issues/24578)
 - Do not free BT memory when in use [#24480](https://github.com/arendst/Tasmota/issues/24480)
 - Berry avoid `tasmota.wifi()` returning bad values when wifi is turned off [#24505](https://github.com/arendst/Tasmota/issues/24505)
diff --git a/tasmota/tasmota_xdrv_driver/xdrv_45_shelly_dimmer.ino b/tasmota/tasmota_xdrv_driver/xdrv_45_shelly_dimmer.ino
index 0c9e3ad5d..de26d8399 100644
--- a/tasmota/tasmota_xdrv_driver/xdrv_45_shelly_dimmer.ino
+++ b/tasmota/tasmota_xdrv_driver/xdrv_45_shelly_dimmer.ino
@@ -273,8 +273,8 @@ bool ShdSerialSend(const uint8_t data[] = nullptr, uint16_t len = 0)
 
     while (retries--)
     {
-        ShdSerial->write(data, len);
         ShdSerial->flush();
+        ShdSerial->write(data, len);
 
         // wait for any response
         uint32_t snd_time = millis() + SHD_ACK_TIMEOUT;