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Lab 3: OTA Firmware Update

Overview​

Over-the-Air (OTA) updates let you upgrade device firmware remotely — no physical access needed — which is essential for maintaining deployed IoT fleets. This lab adds OTA to the temperature/humidity monitor from the previous labs.

Requirements​

Design and implement an OTA update system for an IoT device on the Core-IoT platform, using an ESP32 / ESP32-S3 and a DHT20 / DHT11 sensor.

Approach​

  1. Set up the ESP32 with firmware that reads sensor data and sends it to an IoT dashboard.
  2. Implement an OTA update mechanism over HTTP or MQTT; deploy an update server and host a new firmware version.
  3. Trigger the update remotely and verify the new firmware runs correctly.

Test plan​

  • Firmware upload test: upload a new version to the server and trigger an OTA update.
  • Data integrity check: verify temperature/humidity keep streaming correctly after update.

Security (design only)​

Write down your solutions (no implementation required): firmware signing and validation before installation, and authentication to prevent unauthorized updates.

Questions​

  • What security measures prevent unauthorized OTA updates?
  • How does your mechanism handle network interruptions?
  • How do you verify the integrity of new firmware before applying it?