How to Update IoT Devices: A Complete Guide to Secure Firmware Updates

Types of IoT Updates

IoT devices require different types of updates depending on their functionality and security needs:

1. Firmware Updates (OTA). Over-the-Air (OTA) updates remotely push new firmware via BLE, Wi-Fi, or cellular networks. These updates are essential for bug fixes, performance optimizations, and security patches. However, IoT OTA updates require robust fail-safes to prevent update failures or bricked devices. A well-structured update process starts with selecting the most suitable IoT connectivity technologies to guarantee seamless data transmission and device communication.
2. Security Patches. Targeted updates that fix vulnerabilities before they can be exploited. With unpatched firmware accounting for 60% of IoT security breaches, as stated in the IoT Security Foundation report, timely security patches are critical to reducing attack surfaces.
3. Feature Enhancements. Updates that introduce new functionalities to IoT devices in the field, such as improved BLE range, better power efficiency, or additional sensor capabilities. These updates help companies extend device lifecycles without costly hardware replacements.

Let’s highlight key action points:

1. Consider OTA for efficiency — manual update is impractical for large-scale IoT deployments.
2. IoT OTA updates are ideal for small firmware changes, but require stable connectivity — implement reconnection logic to handle dropouts.
3. A hybrid approach balances security, scalability, and flexibility — perfect for devices with mixed connectivity options.

Best Practice:

• Staged rollouts ensure that updates are initially deployed to a small batch of devices, allowing you to monitor for failures before a full-scale rollout.
• Delta updates, sending only modified parts of the firmware, reduce the risk of failure.
• Fail-safe & rollback mechanisms should be implemented to restore devices to their last stable state if an update fails. This approach minimizes damage to the device fleet and improves reliability.

📌 Secure and scalable firmware updates are just one part of the bigger picture. If you're planning an IoT project, understanding IoT application development cost will help you optimize resources.

End-to-End Encryption & Secure Boot

Challenge: IoT devices often handle sensible data, which requires strict adherence to regulatory standards.

Best Practice:

• AES-256 encryption secures the firmware during transfer to protect against unauthorized access.
• Secure boot ensures that only authorized firmware is installed, maintaining integrity and preventing malicious software from being executed.
• FIPS 140-3 and ISO 27001 standards should be followed to ensure proper encryption and data protection mechanisms are in place, especially in industries like healthcare and finance.

Seamless OTA Updates & Transparent Communication

Challenge: Poor IoT device update experiences frustrate users, erode trust, and reduce retention rates.

Best Practice:

• Silent background updates minimize downtime and user interaction, enhancing the user experience.
• Clear update logs inform users of new features or fixes, building transparency and trust.
• Failover mode should allow devices to remain partially functional even if an update fails, ensuring users don't experience complete downtime.

Technical Best Practices

Let’s move to the technical issues and what you can do to solve them.

Adaptive BLE Transmission & Error Recovery

Challenge: BLE connectivity is prone to interference, which can lead to failed or delayed updates.

Best Practice:

• Adaptive BLE transmission dynamically adjusts based on environmental factors like signal strength and interference.
• Error recovery & retry logic ensures that IoT updates can resume from the point they were interrupted, rather than starting over.
• Multiprotocol support should be incorporated to switch to Wi-Fi or LTE when BLE is unreliable, ensuring a more robust connection for firmware updates.

Modular Firmware Architecture & Automated Testing

Challenge: Cross-platform and chipset compatibility issues can complicate firmware updates.

Best Practice:

• Modular firmware architecture separates core logic, connectivity, and security layers, making updates easier to manage across different devices and platforms.
• Automated testing through CI/CD pipelines with hardware-in-the-loop (HIL) simulations ensures that updates are compatible across different devices and OS versions. This is crucial when dealing with multiple chipsets, like Nordic, TI, or Dialog.

Low-Power Update Strategies

Challenge: Frequent IoT device updates can drain battery life, especially in low-power smart devices.

Best Practice:

• Delta updates reduce data transfer size by only sending updated parts of the firmware, reducing energy consumption.
• Update scheduling ensures that updates occur when devices are connected to power or during periods of low activity, preserving battery life.
• Efficient BLE packet handling compresses data to further reduce energy consumption during the process.

Secure OTA Infrastructure

Challenge: Unsecured firmware updates are vulnerable to cyberattacks, putting devices at risk of being hijacked or infected with malware.

Best Practice:

• Cryptographic signing of firmware ensures that updates are authentic and have not been tampered with.
• Anti-rollback protection prevents attackers from downgrading firmware to exploit known vulnerabilities.
• Encrypted update channels, such as TLS 1.3, ensure that firmware is securely transmitted and protected from man-in-the-middle (MITM) attacks.

# 1: Staged Rollouts

• Start with 5-10% of devices and monitor performance before full deployment.
• Implement auto-recovery mechanisms if issues are detected.
• Use A/B testing to compare firmware versions in real-world conditions before full rollout.

# 2: Delta Updates for Efficiency

• Send only modified firmware sections instead of full binaries to reduce update size, power consumption, and transfer time.
• Use LZMA or Brotli compression to further reduce data size.
• Validate firmware integrity after each segment to prevent corrupted IoT updates.

# 3: Fail-Safe & Rollback Plan

• Store previous firmware versions on the device to allow instant rollback if an update fails.
• Use a dual-bank firmware architecture. One partition holds the active firmware, and another stores the new update until verified.
• Implement watchdog timers to detect update failures and trigger an automatic rollback.

Post-Update Actions

After deployment, you should continuously monitor the performance of your devices to catch issues before they escalate.

# 1: Monitor Device Logs

• Capture error reports, update success rates, and firmware performance post-update.
• Use cloud-based analytics dashboards for real-time tracking.

# 2: Automate Alerts for Failures

• Set up automated alerts for failed IoT device updates, security breaches, or abnormal device behavior.
• Integrate real-time monitoring tools (for example, Datadog and AWS IoT Device Defender) to detect anomalies.

# 3: Validate BLE Connection Stability

• Run BLE diagnostics to check for latency spikes or dropped packets after updates.
• Reconnect devices automatically if BLE connection is disrupted.

To solve these challenges, we developed a native module that:

• Performed reverse engineering of the original protocol to identify and fix inefficiencies in the IoT update process.
• Optimized OTA update speed, reducing delays and ensuring reliable firmware deployment.
• Enabled seamless BLE communication across all scooter models by creating a generic protocol handler.

Egret’s app now delivers faster and more reliable OTA updates, significantly improving customer retention and user satisfaction.

Let’s find out what technologies are going to facilitate firmware updates.