Hi,
For your use case, a robust and reliable firmware update mechanism can be implemented by following these guidelines:
In your application, implement a dedicated function to securely receive and store the new firmware file in your external flash. This can be efficiently achieved using your existing LWIP webserver interface.
Develop a custom bootloader that:
- Executes on system startup and checks external flash for new firmware.
- Verifies the integrity and authenticity of the stored firmware (e.g., CRC checks or cryptographic validation).
- Writes the validated firmware from external flash into the main MCU application area.
- Handles rollback scenarios in case the update fails, thus ensuring a safe fallback to a previous stable version.
Best Practices to Ensure Robustness:
- Always include checksum (CRC, SHA, etc.) or cryptographic signature verification before applying the firmware.
- Consider using a dual-bank or backup firmware approach, allowing the system to revert to a known good firmware in case of an issue.
- Ensure the bootloader updates firmware atomically, avoiding partial writes that could lead to system failure.
- Design your bootloader to handle unexpected resets or power loss during firmware updates gracefully.
By following these tipps, your firmware update process will be both robust and fault-tolerant.
