ESP8266 Community Forum

For some time I have been using my ESP2866-1 with a specific sketch from Arduino IDE, so admittedly my flashing sikills got rusty... Still, I cannot figure out what I am doing wrong.

My current sketch is set to connect to my WiFi and react to specific commands - it provides feedback both on the HTTP page and through serial communication. It does both - that is how I know both that the module is working and that the serial communication is working. So, if I am correct, the only thing needed to start flashing is to close the serial comm window, pull GPIO0 to GND, reset the module and start flashing with esp_flasher... The problem is that it does not work - esp_flasher outputs "Failed to connect". What am I missing here?

Do you have a pullup resistor (I normally use 3k3) from 3V3 to the GPIO2 connection?

Most diagrams for flashing do not mention this...

Anyway, I have included the resistor in my layout and nothing changed.

I have used my Arduino UNO as a TTL connector in case my other one was not working properly and it is exactly the same: ESP8266 happily communicates with me over serial, just like prescribed in its current firmware, but refuses to communicate when I try to update the firmware.

Pulling GPIO0 to ground before startup does make a difference, as ESP does not run my old program then...