I am trying to install AT command official firmware and so far I am not able to find a reliable way to do that. I have tried using the official flasher tool from Espressif's website but I do not know what hex values should I put in that and what bin files and in which order should I put in that. I have tried so many tutorial and I think all of them are out of date in firmware version.(Also which firmware should I download from the website and my esp8266 module is 8 Mbit module.)


1 Answer 1


AT 1.7

AT firmware 1.7.x is build on Espressif NonOS SDK 3.

The Espressif AT binary is built for 2MB-c1 flash partitioning. Flash Download Tool corrects it for 4 MB flash, but for esptool you should use the --flash_size 2MB-c1 option and the corresponding addresses.

esptool.py write_flash --flash_size 2MB-c1 0x0 boot_v1.7.bin 0x01000 at/1024+1024/user1.2048.new.5.bin 0x1fb000 blank.bin 0x1fc000 esp_init_data_default_v08.bin 0xfe000 blank.bin 0x1fe000 blank.bin

The AT 1.7.4 version has bin file for flashing to 1 MB flash.

esptool.py write_flash --flash_size 1MB 0x0 boot_v1.7.bin 0x01000 at/512+512/user1.1024.new.2.bin 0xfb000 blank.bin 0xfc000 esp_init_data_default_v08.bin 0xfe000 blank.bin 0x7e000 blank.bin

For some esp8266 modules you will have to add --flash_mode dout before --flash_size.


AT 2.1

AT firmware 2.1.x is build on Espressif RTOS SDK for esp8266 and esp32.

The flashing command of AT2 with esptool is esptool.py write_flash @download.config. I recommend to change in download.config file flash_mode to qio if your ESP module supports it and flash frequency to 40MHz if your module doesn't support 80MHz.


Flashing tools

  • \$\begingroup\$ Of the above, it looks like only the 1MB option of the 1.7.x firmware will work for flashing to a 1MB device like the ESP-01S and 1MB versions of the ESP-01. I'm guessing 2.x is abandoning devices with <2MB flash. An argument in favor of the ESP-12F module instead of the ESP-01 series - an upgrade albeit with different pinout and harder for hobbyists/prototyping. \$\endgroup\$
    – tom r.
    Mar 6, 2021 at 5:25
  • 2
    \$\begingroup\$ @tomr., the 2.1 can be build for 1 MB. here is a build for esp-01 github.com/jandrassy/UnoWiFiDevEdSerial1/wiki/files/… \$\endgroup\$
    – Juraj
    Mar 6, 2021 at 8:47
  • \$\begingroup\$ github.com/CytronTechnologies/esp-at-binaries also provides binaries for ESP-01 for 2.2.0 firmware. I understood after a lot of head scratching that the UART pins were moved in official firmware, thus no response for AT on updating the firmware. \$\endgroup\$
    – EarthLord
    Nov 22, 2023 at 10:34

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