[BK7231N/CBU] help needed with reprogramming the circuit in the smart valve controller

A warm welcome to you all

I'm not quite sure where to post this, so I'm posting here.
Let me start by mentioning that this is my first attempt at reprogramming a WiFi smart device using the OpenBK tool.
I need help with the CBU chip (BK7231N), namely in no way can I get past the point where the program requires a reboot or power off.
I have connected the circuit according to the markings on the back of the board and following a similar device https://www.elektroda.com/rtvforum/topic3994294.html.
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The programmer used is a CH340, power connected 3.3 volts from a separate power supply, of course I tied all the grounds together, but the power from the programmer was not connected.
As I couldn't get it to program through the lead-out programming pads at first, I decided to use the hardware and desolder the guy, but it looks like it's glued to the other board, so I let the wrangling go and so cut the power line from the rest of the chip and added wires to make it easier to hook up, but that didn't help either. I'll also mention that I had previously programmed a circuit on a relay that shorted my CEN pin to ground for 0.25 seconds, so this method didn't work for me (at least at the moment), I tried disconnecting the 3.3V supply line, but that didn't help either. I've also tried different configurations with different baud rates, but that doesn't work either.

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Screenshot of the program

Can you advise me what else I can do, I would appreciate any advice.

Is the Rx/Tx on the board connected to something? E.g. to a relay, an LED, a button with a capacitor

From what I've looked at the board, I don't see them connected anywhere else but to the circuit. When I get home I'll check some more.

Basic things to do/check:
- swap RX with TX
- shorten the wires - however, in the pictures they are long
- another USB to UART converter - we had such cases on the forum already
- check if something else is connected on RX/TX - typical problem, that is why I often desolder the whole module
- different baud rate to try (higher or lower...) - although you wrote that
- what power supply - directly from 3.3V from the USB to UART converter is not enough current - although in the post you wrote that external, it's probably ok....
- solder the module - you mentioned, but oddly enough, I haven't encountered it being glued together
Basically it has to work, worst case scenario if you cover the postage then I can try to zflash it, but I think it will work for you.

I don't use CEN myself, I just cut the power, sometimes I have seen that the capacitors on the board mix up the power cut a bit, and a few times I remember using a not very recommended but working method - a modification of the power cut version - where when I cut the power, I also short the 3.3V line on the WiFi module side (not the power supply!) to ground so that the capacitor gets rid of the rest of the energy.... and then back to the power supply

And how many COM ports do you have in this program? Maybe you are selecting the wrong one.

Ok, thanks a lot for your help, it worked, what I changed with your advice is:
- Shortening the Rx and Tx wires,
- Changing the programmer to a different one, but still CH340 (only one I had in the drawer),
- I swapped the places of the Rx with the Tx.
After doing a lot of combinations, getting to these steps and triggering with my circuit on the relay (I also tried the method with disconnecting the power supply and shorting during these different configurations), finally something else showed up in the program console, but after a while an error showed up, then I decided to switch from baud rate 921600 to 115200 and this worked, the machine moved on.
Again, thanks a lot for your help and for believing I can do this, if it's useful/necessary I can make a new topic/thread with this device, as I don't think I've seen one with this chip, but that's only after I get back from holiday in 2 weeks.

If you want me to help you with the content to make it suitable for the main topic, send me a draft to PW and I will help, if not, you can upload it yourself. We are committed to growing our Device List, there are almost 800 entries already, it would be nice to reach 800 devices this year:
https://openbekeniot.github.io/webapp/devicesList.html