@divadiow Big thanks for your help.
I have change TX and RX, i have short wire and add a other 3V3 power and soldering the TX and RX on circle.
But flash don't run :-\
I have make a video of complete installation.... i have no idea.
I would say your circut have no chances to work. You've made at least two mistakes:
- your wires are way too long, it has been proved many times on this forum that shortening the wires helps a lot
- you seem to be powering your device from 3.3V directly from USB to TTL, it does not have enough current to power WiFi module well
If you really don't want to use external LDO like I do on my videos https://www.youtube.com/@elektrodacom , you can consider taking 5V from USB and connecting it to the INPUT of AMS1117-3.3V on the board, so the WiFi module still gets 3.3V from AMS1117-3.3V output. This method may or not may work, depending on the capacitors on the board...
>>21357215 Hello, thank you for your recommendation. I have tested with a little wire of 15 cm and I have made an external power by esp32 but nothing. I'm lost.... I don't understand. I have made flashing with your help for T34, perfectly but with this board, I don't understand ...
I received a different version of the mini smart switch. I was unable to flash the board over the air with tuya cloudcutter. As you can see the T34 pins are hidden. I understand that I can get 3.3V and ground pins from the AMS1117 chip but I have no idea where to get TX and RX from. Does anyone have the same board and was successful in flashing it?
For the new chips, it's almost impossible to do it without microsoldering. The pad for the pin 25 is pulled up with a 10k resistor and a capacitor, I don't know why. I had to remove both. Also, the pad for the pin 26 is not connected to anything. I had to remove the chip, add a fake pad, resolder the chip and finally flash firmware.
Images for reference. I'll only buy modules from the "brand" Avatto from now on. They're much simpler to flash and to work with, and the build quality is better than the Tuyas. If you're buying modules to flash new firmware, I highly recommend buying from this brand. Cheers!
Hello, I also have Smart switches like the one described at the beginning of the topic and I also have problems with them like many of the writers, except that I have found a workaround for the problem. In a nutshell: - layout, connection as in this post - problem with reading and writing via BK7231Flasher (Ubuntu 24, wine), the program reads keys and efuse and crashes on reading memory, writing erases memory and reports an error.
In the end instead of BK7231Flasher I used hid_download_py for both read and write memory. As a batch I used OpenBK7231N_QIO_1.18.92.bin downloaded on previous attempts by BK7231Flasher. The module started, it works, it integrates with the HA without any problem, even the pin configuration loaded automagically.
I attach a snapshot of the clean (unconfigured) module and cobbled together logs from my failed attempts to use BK7231Flasher.
The discussion focuses on flashing T34-based smart switches purchased from AliExpress, which use the BK7231N chip, with custom firmware such as OpenBeken (OBK), Tasmota, or ESPHome-style firmware. Two hardware variants were identified: one with the pushbutton on the back and another on the front, both sharing the same baseboard design. Users encountered challenges flashing these devices using the Tuya Cloudcutter due to firmware version 1.3.10 being non-flashable via cloud methods. Successful flashing requires direct UART access, often achieved by soldering or using needle pins on test pads or chip pins 25 (RX) and 26 (TX). A pull-down resistor labeled BR4 on the PCB aids in accessing the TX pin. Power supply stability is critical; USB-TTL adapters often lack sufficient current, so external 3.3V power supplies or powering through the AMS1117-3.3V regulator input are recommended. Short, direct wiring and proper connection of RX/TX lines (crossed correctly) are essential to avoid communication errors. Flashing tools like BK7231Flasher sometimes fail due to power or connection issues; alternatives like hid_download_py have proven more reliable. Some users reported needing to overwrite the bootloader to restore UART functionality. For newer or different board revisions, microsoldering and hardware modifications (removing resistors/capacitors) may be necessary. The community shared various soldering techniques, including solder-less needle pin methods and glue gun fixtures for stable connections. MQTT integration with Home Assistant works well after flashing, though some configuration flags may need adjustment to enable full telemetry. Additionally, a variant with an unmarked RF chip (possibly SYN531R) was discussed, with suggestions to analyze its protocol for remote control support. Overall, the thread provides detailed practical advice on hardware identification, wiring, power considerations, flashing procedures, and firmware configuration for T34/BK7231N smart switches from AliExpress. Summary generated by the language model.
