Udemy has a course on IoT security. The curriculum includes 23 lectures:
Author Introduction and Table of Content
Introduction to IoT and IoT Foundation
Section 3 : Getting started with IoT Security
Firmware Hacking 101
Automated Firmware Analysis
Conclusion and Discussion
https://www.udemy.com/introduction-to-iot-security-and-hacking-iot-firmware/?platform=hootsuite