(This is my first original contribution post, please be nice)
I accidentally uploaded tasmota-minimal and bricked my kettle so I poked around trying to figure out how to flash via serial. I figured it out. BUT, I would honestly recommend other methods before this, including: 1. Flash OTA using Tuya Convert; 2. Use Google Assistant relay to mimic “hey google, turn on the kettle”; 3. Flashing via serial (detailed below). This only gives enough detail for someone familiar with serial flashing already.
Inside the kettle & accessing the flashing points on the ESP8266
It was actually really easy to get into the kettle and see all the electronics including the ESP8266 chip running the smarts of the device. While I have flashed heaps of sonoff devices and d1 minis over serial I was completely lost. There’s no obvious markings for VCC, GND, RX and TX so I thought I’d point out to other novices (like me) how to do it.
The chip appears to be an ESP8266. The model is TYWE3S. If you get stuck on the steps below, check these two articles that helped me: about the TYWE3S (here) and the section on this page title Flashing - Preparation (here).
- Extract the computer board (unscrew base, remove handle cover, remove the computer board from the handle).
- Get ready to flash, part 1: attach cables from your serial adaptor to the ESP8266 board, like this.
- Get ready to flash, part 2: (as per Flashing - Preparation subheading) You need to GPIO-0 to the GND to enable flashing mode - i soldered a wire between.
- (also as per link in #3) Disable the MCU during flashing. (Warning: I have little expertise and fumbled my way through this. I think I was probably a few mins away from overheating the whole thing - there is probably a better way but I had no guides to follow and nothing to lose.) The article gives 3 options to disable the MCU sending data on TX and RX. I went with option 3. The way I did this was probably pretty dodgy, and definitely smelt a bit like burning, but I got away with it: link the GND of the ESP chip with either VDD on the underside. I knew this worked when the lights of the display did not light up.
- Unlink GPIO-0 and GND from ESP chip) and power back up so that it is no longer in flashing mode. As per any other flashing process, it should produce its own Wifi network, join, configure as per many other guides, and then set up kettle as per the original post.
Good luck to anyone else doing this!