[BK7231N/CBU] Intelligent Spray System WD-01CE Pump how to flash, getting bus failed

I bought the Intelligent Spray System WD-01CE (which also goes by some different names).

It's used to spray water, therefore contains a pump, a button with an LED, and a piezo module.



It's pretty easy to unscrew after removing the 4 pads over the screws.



After unscrewing, you can see the pump and the board.



To remove the board, 3 screws need to be unscrewed.



According to my research on https://developer.tuya.com/en/docs/iot/CBU-NL-module-datasheet?id=Kbaeq6j53y0yg, it uses the BK7231N chip the pins are the following:



The pinout for setup is:

P6 - Buzzer
P8 (PWM2) - Btn
P16 - REL
P20 - LED_n

First of all, please check if there is anything else connected on UART lines. Are they used for something else than flashing, maybe for a button, or for a relay, or something like this?

Is this your first Beken chip you are flashing? Have you made sure to provide enough current for your device? Have you tried swapping RX and TX? Are you flashing it in BK7231N mode? BK7231T mode will not work for N.

Yeah, it's my first time flashing.
I solved it. On the Tuya sheet, they showed it from the bottom, so I used RX01 and TX01, which are for logging. On the other side, there are the RX and TX pins for programming (hard to solder).

The only thing I am now missing is, what would you set for P6 as it is a buzzer? In the dropdown menu, I didn't find something like it. Currently, I have set it as LED.

I didn't have any buzzer devices yet. Maybe you can try to set it as PWM, enable "show RAW PWM controllers" flag and then check if doing set channel can get you a tone out of it?

a little bit more info derived from a WD-01CE backup sourced elsewhere (thanks @piotrszulc1). all info is taken from this file, attached.

boot:

config data in binary after device config is pulled down from Tuya



Added after 4 [minutes]:

how it presents in Tuya app


fw v1.1.7 is on the Cloudcutter known patched list

Added after 3 [minutes]:

@kilianeller12 did you get a fully working device with OpenBeken?