Improvements

[LuKks]

Investigate:

• Sign and validate updates so devices doesn't have to trust the source (e.g. HTTP server)
• Support Secure Boot v2 so it's easier
• Pre-encryption would be nice also
• Root CA can expire or need an update, edge case would be a device is offline for months
• Backend could optionally encrypt and sign the firmware

Also thinking:

• User uploads their usual .bin file to the server
• ota-backend can extract the ELF hash from .bin using esptool.py
• Devices can use esp_ota_get_app_description() -> app_elf_sha256

python3 -m esptool --chip=esp32 image_info ./firmware.bin --version=2 https://github.com/lukks/iot-dev/blob/main/lib/elf-hash.js

That way the device can detect it's not running the latest firmware when force uploading a different one via USB. It's not real protection, it's just so the device is not stuck without OTA updates on development

[LuKks]

Unit tests are missing also