[BK7231T - WB2S] Moe's House WiFi+RF433 Single Fire Switch Getting Bus Failed

Good morning all!
I am new to this forum as I am very excited to get the OpenBK7231T_App up and running.
I have been using Tasmota for a long time with various ESP based chips and love its stability and consistency and would love to do the same with the Tuya based switches I have.
As mentioned in the subject above, I have many Moe's House WiFi RF433 Single Fire Switch (mine are the 3 gang version):

[url=]https://www.amazon.ca/Generation-Single-Switch，No-Neutral-Compatible/dp/B08S2R6V6W[/url]

I have traced the 4 lines to on the WB2S controller to jumpers on the PCB and soldered wires accordingly:



In trying to use the BK7231 GUI Flash Tool 1.0.5 I continuously get the Getting Bus Failed message until it times out after 100 tries.
The interesting thing is that through MANY attempts I did get the 'Getting Bus Success!' msg to then only have it tell me that I couldn't set the baud rate to 921600 ... which happened twice.

I have tried alternate baud rates, I have tried connecting the UART first then opening the flashing tool (and various variations on this as well).

You will notice in the image that I have placed the ground wire across a small breadboard to easily cycle the power on the device when it is time to reboot.

I was wondering if anyone here may have had success with this particular Moe's House switch and if anyone could provide some advice.

Thank you very much for all your hard work and I look forward to using this new firmware!

-=O=-

Hello, can you post better photos of the board?
Have you tried bkWriter 1.60, just to be sure that's not the fault of the relatively new tool?
https://github.com/openshwprojects/OpenBK7231T/blob/master/bk_writer1.60.zip
Are you aware that some devices might be using TX or RX for another purpose, like for a button, and sometimes it might be needed to temporarily cut the trace, like in one of our Elektroda videos:
https://www.youtube.com/watch?v=PKkiqDNFIx8
We also had the same issue while flashing a wall switch, but in that case we just desoldered a SOIC chip:
https://www.youtube.com/watch?v=Yb3zXtBdSnE

Hi p.kaczmarek2 and thank you for the quick reply!
Here is a closer image of the board and I have moved the soldered wires to get a better view:



I have also tried the bkWriter 1.60 with no luck...

You may be correct about the TX and RX being used otherwise as all I did was use a continuity meter to locate the leads on the (seemingly) unused solder pads (as you can see where I soldered). The other difficulty is that the SOIC is laid flat on the PCB so the lower pins are difficult to access.

I am replying before watching your YouTube videos, but will check those right now.
Thanks again and I look forward to your reply

-=O=-

I can clearly see that your device is a TuyaMCU device where 1RX and 1TX is used to communicate with external MCU in TQFP case.

There are multiple options to do from here:
a) cut the traces and reconstruct them after flashing
b) desolder WB2S, flash, solder back
c) desolder chip in TQFP....
d) find datasheet of TQFP mcu chip and see if it can be put in RESET mode - maybe one of the pins is RESET?
e) check second side of the board, maybe there is a resistor on each RX/TX line...
I don't have any more ideas. You will also need to do TuyaMCU configuration for that switch after flashing, but we already support TuyaMCU so we will figure it out

Thank you so much for the help p.kaczmarek2!

I have watched both videos (and subscribed) and have already learned so much from them as well.
I am assuming you are done for the day but I will research further and get back to you soon!

Cheers from Canada!
-=O=-

Well, the only thing I could add is that it might be worth to do first an UART packet capture before flashing, so we can figure out dpIDs easily for TuyaMCU.
Just connect RX of USB to TTL dongle to RX (and then to TX) line of WiFi module and try to observe (and save to file) TuyaMCU communications in hex...

TuyaMCU is using so-called "dpIDs" for variables like power on/off state of switch, and you need to figure out them per-device so we can use them in OBK (or in Tasmota) to control device.

Here is an example of TuyaMCU dimmer:
https://www.elektroda.com/rtvforum/topic3898502.html
but the same logic applies to non-dimmers as well

Heya p.kaczmarek2!!

I just wanted to let you know that I got at least the first step working!
WOOHOO!!

I ended up trying to remove the WB2S from the PCB using a soldering iron and I ended up ripping 3 of the pads off the bottom
.. perhaps I can attempt to fix that later ... damn it!

Sooo... I took a second Moe's House switch (as I have several) and used a heat gun this time and it just fell off the PCB.
I soldered the wires directly to it and it flashed without issue.

It took a few times to get it to connect to the network here .. Is the SSID case sensitive?

But.. it is now done!

Next is to re-solder it to the PCB and then figure out the template.

Thank you so much for your help as I am so glad to be rid of Tuya!!!

Which pads have been damaged? It should be possible to reroute workings pads to the required signals.

I pulled off the VBAT and TX and RX pads...
However, it appears that I have somewhat reattached the VBAT pad.

:(