imgtool is a Python library and command-line tool primarily designed for image signing and key management within the MCUboot ecosystem. It facilitates secure firmware updates for embedded systems by providing functionalities to generate cryptographic key pairs, extract public keys, and sign firmware images with necessary headers and trailers for bootloader verification. The library is actively maintained as a core component of the open-source MCUboot project, with releases generally aligning with MCUboot's development cycle.
pip install imgtoolNo compatibility data collected yet for this library.
This quickstart demonstrates how to generate a cryptographic key pair and then use it to sign a dummy firmware image. The `sign` command requires specific parameters (`--header-size`, `--align`, `--slot-size`) that must match your target MCUboot configuration.
Use `pip install imgtool` for simpler dependency management, or manually install dependencies from `scripts/requirements.txt` if using the script from the MCUboot source tree.
Always consult your specific MCUboot build configuration (e.g., Kconfig options in Zephyr) to determine the correct values for `--header-size`, `--align`, and `--slot-size`.
Always generate your own unique, strong cryptographic key pairs for production use, and protect your private keys diligently.
Avoid using `--rsa-pkcs1-15` unless absolutely necessary for backward compatibility with older MCUboot versions. Default RSA signing without this flag uses a more robust algorithm.
Ensure you have the correct Python environment activated and install `imgtool` and its dependencies using pip: `pip install imgtool` or `pip install --user -r scripts/requirements.txt` if installing from the MCUboot repository.
If installed via pip, ensure your Python environment's script directory is in your system's PATH. If installed manually, ensure the `imgtool.py` script (or its wrapper) is placed in a directory listed in your PATH, or execute it directly using `python /path/to/imgtool.py`. For global installation, consider `sudo python3 setup.py install` or manually copying it to a system-wide bin directory.
Re-download and re-install `imgtool`. If installing via `pip` on Windows, ensure your Python installation is healthy. If using a standalone `imgtool.exe`, try obtaining a fresh copy from a reliable source. Running a Windows Update or an antivirus scan might also help resolve underlying system issues.
Ensure you are using a compatible version of `imgtool` with your generated images, preferably the latest stable release. If the issue persists with images from Zephyr's latest release, check for open issues on the MCUboot GitHub repository or try regenerating the image.
Run your command prompt or terminal as an administrator when executing `imgtool` commands. Alternatively, ensure the target directories and files are not read-only and are not being used by other processes. For Windows users, running `pip3 install imgtool` and then retrying with a pristine build directory is also a recommended fix.