mmakaay
commented
1 year ago They cannot disable the serial output that the ESP32 dumps out when booting up. There will always be at least some output at that point, before the firmware takes over logging. So if you see no output at all, my guess is that the problem lies further down the chain.
The device behaviour changing when you ground GPIO0 sounds good. Since you have tried multiple serial clients, the serial connection seems the culprit here.
Did you try the CP2102 USB-TTL with another device to see if you can see serial output from it?
I have a CP2102 USB-TTL, and I hooked it up to the lamp as shows in the instructions. At first I tried holding the wires but I wasn't getting anything on serial so I soldered GND, TX, RX. And before plugging the lamp, I manually short GPIO0 with GND using a breadboard wire with two male ends. I think this part works because when I short GPIO0 to GND, the front panel buttons don't do anything anymore until I unplug replug the lamp.
My problem is that I can't even get anything on the serial console. I tried with the esphome-flasher tool, with screen, with putty. I am in the right group to open the serial device. Tried at 115200 bauds and 9600. Tried swapping TX and RX on the USB-TTL's end. No dice.
I also get nothing on the console when not shorting GPIO0, but it's my understanding the ESP32 is chatty regardless so I should be seeing things too when the lamp is operating normally, right?
I can see the RX LED blinking on my USB-TTL with the lamp in normal mode when I press buttons or the slider, or when the lamp turns on. But nothing shows in my terminal/putty/esphome-flasher. I also can't dump the actual firmware, unsurprisingly.
What am I missing? Could it be Xiaomi disabled serial in their infinite wisdom in an update? My lamp says firmware 2.0.30.