ESP8266 Community Forum

I programmed with Arduino IDE to use GPIO1 and GPIO3 for digitalWrite.
After writing the program and execution, I cannot rewrite any program / firmware using COM port.
Any procedure to rewrite programs?
I spent 2 modules for this issue.

The error message is as follows:
esptool.FatalError: Failed to connect to ESP8266: Timed out waiting for packet header

1 Are you using a 'bare' esp-wroom-02? If not which board are you using?

2 Have you added the esp-wroom-02 to the |Arduino IDE? For details see here:- http://www.deviceplus.com/arduino/using-esp-wroom-02-wifi-module-as-arduino-mcu/