Bricked BK7231N generic smart switch using tuya-cloudcutter. Now I need to identify serial pinout

First time having to deal with Beken's MCU, had experience flashing ESP8265.

I've yet to figure out what went wrong but after flashing via tuya-cloudcutter with OpenBeken 1.17.105 firmware something went wrong and now the led is faint and pressing or holding the button does nothing.


So now I need help to identify which pin is tx, rx, 3v3, gnd and reset pin to flash the firmware via serial port.



Considering that there are 2 pairs of bridged pins on the right of the chip I cannot find any pinout online that makes sense. The silk screen text also doesn't help me much.

Hello, have you tried checking our BK7231 datasheet topic?
https://www.elektroda.com/rtvforum/topic3951016.html
You can find BK7231 pinout there:

Dot marks the first pin. It should be easy to identify which is which.

Btw, isn't it the same device that @piratee was flashing? Aubess or something switch?

PS: Did you flash T binary on N device?

p.kaczmarek2 wrote:

Dot marks the first pin. It should be easy to identify which is which.

Well that was the piece of information I was missing. I was dumb and didn't figure out that I needed to rotate the pinout to match the chip...

Anyway, I used a Raspberry Pi 4 with the latest Tuya-cloudcutter from github and placed OpenBK7231N_UG_1.17.106.bin into the custom-firmware folder and ran the script as root. I'm not sure what went wrong but after the second reboot the script ended and I was left with the smart switch in that state.

In a few days I will receive another one identical and I will try again. I don't really care if I break them, I only paid 1,65€ for each of them.



UPDATE:
I received the package early, 10 switches in total, 3/10 are esp8265 so I already know how to handle it. Of the other 7 I received 4 variants, of which 1/7 is BL2028N and the rest are BK7231N.
I guess I will figure it out in a way or another how to flash it correctly...

Also should I upload the picture of the other 3 variants? Are they useful for this forum?

They all should be supported. Please make pictures and read 2MB firmware with our tool:
https://github.com/openshwprojects/BK7231GUIFlashTool
The latest version should extract GPIO config automatically.

Feel free to also include ESP8266 variant photos.

BL2082N is also supported.

Where did you get so cheap modules?

I bought them on Aliexpress. There's a section where all listings are 1.79$ and I saw many listings for wifi switches and random items. I placed multiple orders and I think I bought like 20-30 of them...

It's like a lottery. You buy it not knowing what chip is inside it and after you receive them you crack it open and check.


Here's the picture of some of the non ESP switches I got. Once I finish flashing/bricking every one of them I will figure out how this website works and upload the pictures of them.


Added after 4 [hours] 50 [minutes]:

>>20575666

Well, I found out the reason Tuya-cloudcutter failed. I found the firmware of the switch listed on the wiki page: https://github.com/tuya-cloudcutter/tuya-cloudcutter/wiki/Known-Patched-Firmware.

I was losing my mind on how yesterday I read the entire wiki and I didn't see that page.

The page was created an hour ago. Lol.


UPDATE:
Tried to flash another variant of the switch with firmware 1.2.1 and it was quick and painless.