Programming and Replacing WB3S with CB3S on Tuya Smart Energy Meter SMTONFF

This is a similar device to the one posted here https://www.elektroda.com/rtvforum/topic3933839.html.

It's different in that both the tuya MCU and the BK7231N are on the same PCB, so I wasn't able to program it without removing the WB3S module. Actually replaced it with a CB3S, I had programmed with open becken already - So I am able to make a backup of the flash, if someone can instruct me on how to.

The tuya MCU is under the display, so really - no chance of tracking any wiring.

I had to remove the WB3S using a normal soldering iron. If using hot air there headers and the LCD display would likely be damaged. So, take caution if you're planning to get these.

It seems to be based on the BL0942 too. All the metering functions and relay contact are dealt with by the tuya MCU.

There are multiple ways to do a 2MB flash backup of the device.
First one is to use our flasher:
https://github.com/openshwprojects/BK7231GUIFlashTool
This is the recommended method but it may not work on Linux.

Second way, mostly for BK7231N, is to use hid_download_py:
https://github.com/OpenBekenIOT/hid_download_py
You can see the usage details in readme or on our YT channel.

There is also outdated bkWriter 1.60, but we dont use it these days.

And finally, if you need guidance, you can check our flashing guides:
https://www.youtube.com/watch?v=L6d42IMGhHw&list=PLzbXEc2ebpH0CZDbczAXT94BuSGrd_GoM

For example, in this guide, we've used hid_download_py to backup BK7231N:
https://www.youtube.com/watch?v=2e1SUQNMrgY&list=PLzbXEc2ebpH0CZDbczAXT94BuSGrd_GoM&index=4

Added after 1 [minutes]:

cdtdsilva wrote:

I had to remove the WB3S using a normal soldering iron. If using hot air there headers and the LCD display would likely be damaged. So, take caution if you're planning to get these.

Good point, I am also using this method: