Project 16: OTA Lifecycle Manager (Dual Partition, Rollback Protection, Factory Reset)

Build a full firmware lifecycle engine with dual-slot OTA, health-based validation, rollback safety, settings migration, and factory reset semantics.

Quick Reference

Attribute Value
Difficulty Expert
Time Estimate 2-3 weeks
Main Programming Language C
Alternative Programming Languages C++, Rust
Coolness Level Level 4
Business Potential Level 5
Prerequisites Partition tables, versioning semantics
Key Topics OTA slot management, health checks, rollback policy, migration logic

1. Learning Objectives

  1. Design safe OTA slot transitions.
  2. Implement deterministic rollback triggers.
  3. Manage settings schema migration across versions.
  4. Build a factory reset flow with explicit persistence rules.

2. Theory

2.1 Firmware Lifecycle States

Update systems are state machines, not one-time flashes. Every transition needs validation and fallback.

2.2 Data Persistence Across Upgrades

Settings, identity, and logs have different durability classes and reset policies.

3. Specification

  • Dual-slot OTA install + first-boot validation.
  • Automatic rollback on failed health criteria.
  • Factory reset preserving immutable identity partition.

Output:

I ota: staged v2.5.0 on ota_1
W ota: health check failed -> rollback
I ota: active slot restored to ota_0 v2.4.0
I settings: migration 4->5 done

4. Architecture

[Updater] -> [Slot Manager] -> [Boot Validator]
                          -> [Rollback Controller]
                          -> [Settings Migrator]

5. Implementation Guide

Core question:

“How do I ship fast updates while keeping every device recoverable?”

Design questions:

  1. What marks a build as healthy?
  2. How many failed boots trigger rollback?
  3. What survives factory reset?

6. Testing

  • Power-loss during download/install.
  • Crash-on-first-boot scenario.
  • Migration and downgrade compatibility tests.

7. Pitfalls

  • No persistent health marker after successful boot.
  • Reset logic wiping calibration/identity data.
  • Version policy mismatch between updater and app.

8. Extensions

  • Add staged rollout channels (alpha/beta/stable).
  • Add OTA telemetry dashboard export.

9. Completion

  • OTA flow handles success, failure, and rollback deterministically.
  • Migration strategy is documented and tested.
  • Factory reset behavior matches explicit policy.