Python script to set a Esp-12 in programming mode.

progEsp.py

#!/usr/bin/env python
import RPi.GPIO as GPIO
from time import sleep
# Setup Gpio
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(3, GPIO.OUT) # Pin 3 (Gpio 2). To Esp Gpio0. 
GPIO.setup(5, GPIO.OUT) # Pin 5 (Gpio 3). To Esp reset ("RST").

# Set D0 low
GPIO.output(3, GPIO.LOW)
# Wait
sleep(1)
# Set reset low
GPIO.output(5, GPIO.LOW)
sleep(1)
# "Release" both buttons. 
GPIO.output(5, GPIO.HIGH)
sleep(1)
GPIO.output(3, GPIO.HIGH)