The Internet of Things (IoT) industry is expanding rapidly, with over 30 billion connected devices expected by 2025. As IoT solutions permeate homes and workplaces, performing remote updates is pivotal to enhancing functionality, fixing bugs, and securing devices.

This article will guide you through everything you need to know about remote IoT device updates, focusing on Over-the-Air (OTA) methods.

What Are IoT Device Updates?

An IoT device update refers to installing newly released firmware or software to an Internet-connected device remotely. This allows functionality improvements, security patches, and bug fixes to be delivered seamlessly over the air after devices are already deployed in the field.

IoT device updates target two key components:

Firmware updates: Fix and improve the low-level software, commanding how the device hardware, sensors, and internal components function. Firmware sits close to the bare metal.

Software/app updates: Target higher-level apps, operating systems, and interfaces running on top of the firmware. For example, the smart assistant on a smart speaker.

As IoT permeates business operations and daily life, the ability to update millions of deployed devices easily is pivotal.

Why Remote IoT Device Updates Are Important

There are several key reasons why remotely updating IoT devices over-the-air is important:

1. Security: Identifying bugs and vulnerabilities is common post-deployment. Pushing OTA security patches rapidly without needing physical access prevents devices from being compromised.

2. Add New Features: Devices can get new capabilities and feature upgrades added through OTA software updates. No manual efforts are needed.

3. Reduce Downtime: Updates can be performed while devices operate normally, reducing downtime. Critical for industrial systems.

4. Lower Costs: No manual intervention cuts management overhead and operational costs, especially for large fleets.

Given these benefits, implementing robust and secure OTA update functionality into devices should be a priority from the start when designing IoT solutions.

IoT Device Update Methods

There are two core methods for updating IoT devices:

Manual Updates

This requires physically connecting to each device in turn using a cable or removable storage medium. Manual efforts don’t scale for large networks.

However, manual updates give users full control and maximum security. Some mission-critical devices in the industrial, automotive, and medical fields may still rely on this approach if OTA isn’t suitable.

OTA (Over-the-Air) Updates

OTA updates send and install new firmware/software remotely without any user intervention. This is achieved using wireless communications technology.

OTA updates are preferred since no physical access is required and updates roll out faster across fleets. However, extra security considerations are needed compared to offline manual methods.

Types of OTA Updates

There are three main varieties of OTA updates:

Firmware OTA Updates

OTA firmware updates target the device-embedded software controlling hardware and functionality. Key for:

• Bug fixes
• Performance optimization
• Adding new low-level features

They can overhaul larger functionality aspects compared to small hot patches. Carrying out thorough testing is vital before deployment.

Software/App OTA Updates

These updates target higher-level apps and software systems running on the devices, without altering lower-level firmware.

Software OTA updates allow new user-facing functions, UX/UI changes, and app-level bug fixes. They are less risky than firmware OTAs.

Secure Signed OTA Updates

Whether targeting device firmware or software, IoT OTA updates should be digitally signed by the vendor.

The device verifies the signature’s authenticity before installing the update. This prevents tampering with the update code or malicious code running.

OTA Communication Models

There are three primary communication models for delivering OTA updates:

Edge-to-Cloud (E2C)

E2C has IoT devices connect directly to an update server in the cloud to download updates. It suits devices with constant reliable internet connectivity.

Gateway-to-Cloud (G2C)

G2C uses an internet-enabled gateway device to coordinate and manage OTA updates for groups of IoT devices in its local network that cannot access the internet directly.

Edge-to-Gateway-to-Cloud (E2G2C)

E2G2C combines the previous two approaches. Gateways request update data from the cloud to minimize internet traffic. IoT devices then handle deploying updates to themselves.

IoT OTA Update Process Step-By-Step

Regardless of the exact architecture, the IoT OTA update sequence typically follows this process:

1. Update Development

Developers create and test the new firmware/software update designed to run on the deployed IoT devices.

2. Update Signing

The vendor digitally signs the update files to authenticate they produced the update before distribution.

3. Update Staging

Signed updates are staged on an update server or cloud storage, ready to deliver to devices.

4. Update Discovery

IoT devices periodically check for available updates from the server.

5. Download Updates

If the device discovers an update, it downloads over the air via WiFi, cellular, or another wireless protocol.

6. Install & Verify Update

Received updates are authenticated using the signature key before being installed. After installation, the operation is verified.

7. Confirm Update Success

Finally, devices confirm back to the update server that the installation succeeded, or notes failures.

Engineers monitor dashboards, tracking update progress across device groups and networks to catch issues rapidly. If any devices fail to update, backup procedures trigger to ensure updates eventually go through or rollbacks activate.

IoT OTA Update Management Tools

While OTA capabilities can program directly into firmware, using dedicated IoT OTA software and tools helps streamline large-scale deployments. Solutions typically provide:

• Central dashboard to track device status
• Group/segment devices for phased rollout
• Push updates scheduling when devices are online
• Failure analysis and notifications
• End-to-end update monitoring
• Rollback previous firmware if issues

This removes heavy lifting for engineering teams. Leading options include the Ayla IoT platform, Mender.io, Particle, Zephyr, and many cloud provider tools like AWS IoT OTA Updates.

Security Considerations for IoT OTA Updates

While convenient, IoT OTA updates pose potential security risks. Measures needed include:

Authenticate Servers: Verify update servers using certificates to avoid spoofing.

Sign Updates: Signature validation prevents tampering with update code or images.

Encrypted Delivery: Encrypt updates files as they transfer to devices to maintain confidentiality.

Consistent Hashing: Ensure file hashes match when received before installation to spot corruption.

Immutable Bootloaders: Make bootloaders read-only after verification so malware can’t touch them.

Isolated Execution: Run and validate updates isolated from current firmware until verified as working.

Rollback Firmware: Restoring previous firmware safely prevents bricking from a bad update.

Troubleshooting IoT Device OTA Failures

Despite best efforts, IoT OTA updates don’t always go smoothly. Debugging commonly involves:

1. Check Device Logs – Inspect device internal logs for diagnostics on exactly which update step failed.

2. Test Update in Sandboxes – Try installing the problematic update on clone test devices.

3. Inspect OTA Traffic – Use a sniffer to ensure devices are communicating with updated servers as expected.

4. Validate Signatures – Confirm proper validation checks are carried out when updates are received.

5. Monitor System Resources – Check for low memory, storage, CPU hogging, or contention issues disrupting updates.

6. Review Code Changes – Analyze the updated contents more deeply for bugs.

With insights into root causes, fixes can be made and updates re-deployed.

IoT Device Update Best Practices

Follow these vital IoT OTA update best practices:

• Implement cryptographic signature validation in devices
• Provide enough storage for updates and multiple firmware versions
• Use immutable bootloaders and partition read-only firmware
• Enable automatic failure logging and alerts
• Schedule throttled phased rollouts gradually
• Ensure failsafe rollback mechanisms activate
• Continuously monitor dashboards for uptake status

Conclusion

With experts predicting over 30 billion IoT devices by 2025, the need for efficient, robust, and secure OTA updates has never been greater.

We covered all major IoT remote update approaches – from manual efforts to a deep dive into end-to-end OTA update functionality and architecture options.

By understanding exactly how IoT device updating works and prioritizing security, you can implement systems to keep devices safe and optimized throughout their operational lifetimes as technology progresses.

Frequently Asked Questions About IoT Device Updates

Still hungry for more IoT OTA update tips? Check out commonly asked questions below:

How often should IoT devices get updates?

Aim for at least quarterly updates, syncing with your product roadmap cycles. More frequent monthly updates also work for devices with rapid evolution. However, take care not to “over update” and create user fatigue.

Which wireless protocol is best for IoT OTA?

Low-power WiFi protocols like 802.11ah HaLow suit low-bandwidth IoT devices. Bluetooth 5 Long Range also works for short distances. Cellular networks support remote updates across vast distances.

Can IoT devices recover from a failed update?

Yes – hardened IoT devices contain bootloader mechanisms to automatically roll back firmware if an update file gets corrupted or doesn’t boot properly after installation. This prevents bricking devices.

What causes IoT OTA updates to fail?

Common IoT update failures include insufficient storage space, disabled or missing bootloader rollback, invalid signatures, code bugs failing validation, network dropouts, power loss, and resource contention with existing firmware.

Should I update all my IoT devices simultaneously?

No way! Always use a staggered “phased rollout” approach, updating a small batch of devices first. Monitor for issues before updating the next batch. This isolates failures and reduces disruption.

How do I scale massive IoT device updates?

Use enterprise-grade OTA management platforms providing dashboards for monitoring status across your entire device fleet, automated phased deployments, and remote troubleshooting capabilities.