How do you update and maintain your microcontroller firmware and Linux software in embedded Linux?

Aws freeRTOS with bootloader integration has s3 bucket option for OTA with versioning info maintained. Generally in mcu its majorly with bootloader, application running update feature and application which needs to be updated Skelton is being seen. In Linux there are methods available like RAUC, mender, A/B, SWUpdate, and many more. At Silicon Signals, we have provided many such ota features either over the air or with peripherals like USB to the customers.

Based on my recent experience with BLE-based OTA updates for EFR32 Blue Gecko boards, I find BLE OTA to be highly effective for microcontroller firmware updates. It offers a secure, low-power option that's ideal for devices where power consumption is a critical concern. BLE ensures secure transmission with encryption, making it suitable for environments where security cannot be compromised.

The concept of OTA requires us to analyze the size of memory first to decide the type of OTA. Typically it can be categorized into in-place update or a roll-back update. If you want to add robustness to prevent failure of your MCU then you can choose the roll-back update scenario. As per this process, you will still be able to recover from failures such as loss of power, connectivity etc. However this comes with the expense of flash memory. You can easily understand this concept with the example of swapping by 3 variables. You are required to make partitions of flash memory - download, swap, application. Then the existing application is copied to a swap location. Finally, the downloaded application is moved to the main partition.

- Implement a secure bootloader for microcontroller firmware updates, ensuring integrity and authenticity during the update process. - Regularly apply software updates and security patches to the embedded Linux system, keeping it current and resilient against vulnerabilities. - Establish an OTA update mechanism for both microcontroller firmware and Linux software. - Use version control systems like Git for tracking changes in software, facilitating collaboration, and enabling rollbacks if needed.

Firmware versioning control mechanism is also play vital role while updating firmware. It should be managed and controlled properly with major and minor numbers along with git commit ID which will be useful proper tracking purpose.

Here are some updated strategies that every embedded firmware developer should consider. 1. Manual Updates: user initiates or approves the update process. 2. Automatic Updates: system-initiated, ensuring the system is always up-to-date. 3. Scheduled Updates: Updates are planned and executed based on a predefined schedule. 4. Conditional Updates: Updates are customised and optimised based on system requirements or user preferences. Each update strategy has its pros and cons. -Manual updates offer control but may be prone to delays -Automatic updates ensure constant updating but come with risks -Scheduled updates provide predictability but depend on external factors -Conditional updates offer customisation but require complex configuration

These are some major learnings while working with microcontrollers FOTA on safety critical systems. 1. Dual partition is often essential for safety-critical applications. 2. We have to have a secure boot with a rollback protection feature. 3. Batch update is the strategy to go about FOTA, rather than a bulk update strategy.

Updating your strategies and approaches based on customer feedback is the best way to continuously improve your system performance and stability.