Connect to your ESP chip with a USB serial converter, perhaps it's even built-in depending on the board.
(Download and uzip the ESP8266 AT Firmware zip file. There will be a folder called esp8266/ containing 3 files.
Put the board into bootload mode (if you have to) by pulling GPIO 0 down to ground while resetting. Use the esptool command line to upload the firmware, for example (your serial port name may vary).
esptool.py --chip esp8266 -p /dev/ttyUSB0 write_flash 0 esp8266/AT_firmware_1.6.2.0.bin 0x3fc000 esp8266/esp_init_data_default_v05.bin 0x3fe000 esp8266/blank.bin
or
esptool --chip esp8266 -p COM6 write_flash 0 esp8266/AT_firmware_1.6.2.0.bin 0x3fc000 esp8266/esp_init_data_default_v05.bin 0x3fe000 esp8266/blank.bin
Programming ESP32 SPI Firmware with esptool
The SPI Firmware is much simpler, we use the combine.py file to turn it into one ~1MB file. You can program this into your ESP32 with:
esptool.py --port /dev/ttyS6 --baud 115200 write_flash 0 NINA_W102.bin
or
esptool.py --port COM5 --baud 115200 write_flash 0 NINA_W102.bin
Change the name of the binary file to match, and the serial port of your USB-serial adapter or Huzzah32 UART connection.
Once you upload the firmware, use the same serial connection you used for uploading to see that the firmware 'took' and some status/debug information:
Hit the reset button to see the debug output.
If you have the AT command firmware installed, when you type, characters will be echo'd. You can try typing AT to get an AT OK reply Make sure your terminal software sends new-lines and carriage returns when you hit return or send data. They are required.
