Flashing ESP32 Firmware with esptool: A Comprehensive Guide

This guide provides step-by-step instructions on how to use esptool to manage flash memory on ESP32 microcontrollers, including reading, writing, and erasing flash memory.

Table of Contents

1. Prerequisites
2. Reading Flash Memory
3. Writing a BIN File to Flash Memory
4. Erasing Flash Memory
5. Project Commands
6. Conclusion

Prerequisites

Before you begin, make sure you have the following:

• esptool: Install using pip:

  pip install esptool

• Python: Required to run esptool.

• Firmware/BIN File: The .bin file you want to flash onto the ESP32.

1. Reading Flash Memory

Identifying Flash Memory

Use this command to get details about the flash memory:

esptool --port COM4 --baud 921600 flash_id

Reading Flash Memory Content

To read the first 4MB of flash memory and save it to a file:

esptool --port COM4 --baud 921600 read_flash 0 0x400000 fileread.bin

2. Writing a BIN File to Flash Memory

Writing Flash with Specific Parameters

To flash a .bin file to the ESP32 with specific settings:

esptool.exe --chip esp32 --port COM4 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x0 H:\Blink.ino.bin

Direct BIN File Upload

For a quicker upload without detailed parameters:

esptool -p COM4 write_flash 0x1000 filename.bin

3. Erasing Flash Memory

To erase all contents of the flash memory:

python -m esptool --chip esp32 --port COM4 --baud 115200 --after hard_reset erase_flash

4. Project Commands

Here’s a summary of commands used in this project:

• Read Flash Memory:

  esptool --port COM4 --baud 921600 flash_id
  esptool --port COM4 --baud 921600 read_flash 0 0x400000 fileread.bin

• Direct BIN File Upload:

  esptool -p COM4 write_flash 0x1000 filename.bin

  • Read BIN File and Write to Flash:

  esptool.exe --chip esp32 --port COM4 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x0 H:\Blink.ino.bin

• Erase Memory:

  python -m esptool --chip esp32 --port COM4 --baud 115200 --after hard_reset erase_flash

Conclusion

esptool provides a powerful way to manage ESP32 flash memory, from reading and writing to erasing. By following these steps, you can efficiently manage firmware on your ESP32.

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