espflash

A library and command-line tool for flashing Espressif devices.

Supports the ESP32, ESP32-C2/C3/C6, ESP32-H2, ESP32-P4, and ESP32-S2/S3.

Table of Contents

• Installation
• Usage
  • Permissions on Linux
  • Windows Subsystem for Linux
  • Cargo Runner
• Using espflash as a Library
• Configuration File
  • Configuration precedence
• Logging Format
• License
  • Contribution

Installation

If you are installing espflash from source (ie. using cargo install) then you must have rustc>=1.76.0 installed on your system.

If you are running Linux then libudev must also be installed; this is available via most popular package managers. If you are running Windows or macOS you can ignore this step.

# Debian/Ubuntu/etc.
apt-get install libudev-dev
# Fedora
dnf install systemd-devel

To install:

cargo install espflash

Alternatively, you can use cargo-binstall to download pre-compiled artifacts from the releases and use them instead:

cargo binstall espflash

Usage

A command-line tool for flashing Espressif devices

Usage: espflash <COMMAND>

Commands:
  board-info       Print information about a connected target device
  completions      Generate completions for the given shell
  erase-flash      Erase Flash entirely
  erase-parts      Erase specified partitions
  erase-region     Erase specified region
  flash            Flash an application in ELF format to a connected target device
  hold-in-reset    Hold the target device in reset
  monitor          Open the serial monitor without flashing the connected target device
  partition-table  Convert partition tables between CSV and binary format
  read-flash       Read SPI flash content
  reset            Reset the target device
  save-image       Generate a binary application image and save it to a local disk
  write-bin        Write a binary file to a specific address in a target device's flash
  checksum-md5     Calculate the MD5 checksum of the given region
  help             Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Permissions on Linux

In Linux, when using any of the commands that requires using a serial port, the current user may not have access to serial ports and a "Permission Denied" or "Port doesn’t exist" errors may appear.

On most Linux distributions, the solution is to add the user to the dialout group (check e.g. ls -l /dev/ttyUSB0 to find the group) with a command like sudo usermod -a -G dialout $USER. You can call su - $USER to enable read and write permissions for the serial port without having to log out and back in again.

Check your Linux distribution’s documentation for more information.

Windows Subsystem for Linux

It is not currently possible to use espflash from within WSL1. There are no plans to add support for WSL1 at this time.

It is also not possible to flash chips using the built-in USB_SERIAL_JTAG peripheral when using WSL2, because resetting also resets USB_SERIAL_JTAG peripheral, which then disconnects the chip from WSL2. Chips can be flashed via UART using WSL2, however.

Cargo Runner

You can also use espflash as a Cargo runner by adding the following to your project's .cargo/config.toml file, for example:

[target.'cfg(any(target_arch = "riscv32", target_arch = "xtensa"))']
runner = "espflash flash --baud=921600 --monitor /dev/ttyUSB0"

With this configuration you can flash and monitor you application using cargo run.

Using espflash as a Library

espflash can be used as a library in other applications:

espflash = { version = "2.1", default-features = false }

or cargo add espflash --no-default-features

Warning Note that the cli module does not provide SemVer guarantees.

We disable the default-features to opt-out the cli feature, which is enabled by default; you likely will not need any of these types or functions in your application so there’s no use pulling in the extra dependencies.

Configuration File

The configuration file allows you to define various parameters for your application:

• Serial port:
  • By name:

    [connection]
    serial = "/dev/ttyUSB0"
    

  • By USB VID/PID values:

    [[usb_device]]
    vid = "303a"
    pid = "1001"
    

• Baudrate:

  baudrate = 460800
  

• Bootloader:

  bootloader = "path/to/custom/bootloader.bin"
  

• Partition table

  partition_table = "path/to/custom/partition-table.bin"
  

• Flash settings

  [flash]
  mode = "qio"
  size = "8MB"
  frequency = "80MHz"
  

You can have a local and/or a global configuration file:

• For local configurations, store the file under the current working directory or in the parent directory (to support Cargo workspaces) with the name espflash.toml
• Global file location differs based on your operating system:
  • Linux: $HOME/.config/espflash/espflash.toml
  • macOS: $HOME/Library/Application Support/rs.esp.espflash/espflash.toml
  • Windows: %APPDATA%\esp\espflash\espflash.toml

Configuration precedence

1. Environment variables: If ESPFLASH_PORT or ESPFLASH_BAUD are set, the will be used instead of the config file value.
2. Local configuration file
3. Global configuration file

Logging Format

espflash flash and monitor subcommands support several logging formats using the -L/--log-format argument:

• serial: Default logging format
• defmt: Uses defmt logging framework. With logging format, logging strings have framing bytes to indicate that they are defmt messages.
  • See defmt section of esp-println readme.
  • For a detailed guide on how to use defmt in the no_std ecosystem, see defmt project of Embedded Rust (no_std) on Espressif book.

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.