ESP8266/Reflashing

Firmware Issues

I have had zero luck communicating with the ESP8266 chip. I can't even get the LEDs on the board to light up.

The solution [1] is to reflash the firmware with the AT command binary image. This will, I guess, get the chip to accept AT commands on the serial RX/TX pins.

Downloading AT Firmware Image

Using this guide from Dave Vandenbout at Xess.com [2], which covers reflashing the ESP8266, I downloaded the AT Command firmware binary image, which was version 0.9.2.2.

Link to firmware binary on Google Drive (warning: may disappear at some point) is here: https://drive.google.com/file/d/0B3dUKfqzZnlwdUJUc2hkZDUyVjA/view?usp=sharing

File name of zipped-up binary image is ESP8266_AT_V00180902_02_baudrate watchdog added.zip

Esptool Flashing Software

In the Xess.com guide, Dave uses the Espressif-provided flash program, which is a Windows executable. Fortunately, I am blessed enough not to have any Windows computers, and will not touch it with a ten foot pole. I used the Python/PySerial-based esptool.py from themadinventor on Github [3] instead.

Downloading

You can download esptool from Github: https://github.com/themadinventor/esptool

Installing

You can install esptool manually using python setup.py build && python setup.py install. This will require the Pyserial library.

Alternatively, you can install it using pip: pip install esptool

Using

The basic usage of esptool is as follows:

$ esptool.py -h
usage: esptool [-h] [--port PORT] [--baud BAUD]
               {load_ram,dump_mem,read_mem,write_mem,write_flash,run,image_info,make_image,elf2image,read_mac,chip_id,flash_id,read_flash,verify_flash,erase_flash,version}
               ...

esptool.py v1.1 - ESP8266 ROM Bootloader Utility

positional arguments:
  {load_ram,dump_mem,read_mem,write_mem,write_flash,run,image_info,make_image,elf2image,read_mac,chip_id,flash_id,read_flash,verify_flash,erase_flash,version}
                        Run esptool {command} -h for additional help
    load_ram            Download an image to RAM and execute
    dump_mem            Dump arbitrary memory to disk
    read_mem            Read arbitrary memory location
    write_mem           Read-modify-write to arbitrary memory location
    write_flash         Write a binary blob to flash
    run                 Run application code in flash
    image_info          Dump headers from an application image
    make_image          Create an application image from binary files
    elf2image           Create an application image from ELF file
    read_mac            Read MAC address from OTP ROM
    chip_id             Read Chip ID from OTP ROM
    flash_id            Read SPI flash manufacturer and device ID
    read_flash          Read SPI flash content
    verify_flash        Verify a binary blob against flash
    erase_flash         Perform Chip Erase on SPI flash
    version             Print esptool version

optional arguments:
  -h, --help            show this help message and exit
  --port PORT, -p PORT  Serial port device
  --baud BAUD, -b BAUD  Serial port baud rate used when flashing/reading

I'm not sure about the difference between the memory and the flash.