Secure Storage of Keys:

Safeguard any cryptographic keys used in the update process. Store keys securely, considering the limited storage capabilities of Arduino devices, and avoid hardcoding them directly in the firmware.
Timed and Authenticated Updates:

Schedule updates during predefined maintenance windows and require additional authentication checks before initiating the update process. This adds an extra layer of security against unauthorized attempts to trigger updates.
Regular Security Audits:

Conduct regular security audits of both the update process and the overall firmware design. Identify and address potential vulnerabilities to stay ahead of evolving security threats.
By combining these methods, Arduino-based embedded systems can establish a secure firmware update process, even with limited resources. It’s essential to balance security measures with the constraints of the Arduino platform to ensure effective protection against unauthorized modifications and potential exploits.