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Version: Torizon OS 7.x.y

Bootloader Updates Overview

Introduction​

In this article, you learn why, when and how to perform bootloader updates with Torizon. It covers the preparation and update procedures, its limitations, known issues and technical details, including how bootloader updates relates to major upgrades of Torizon OS.

Bootloader in Torizon OS​

Bootloader is the piece of software that loads the operating system into memory for execution along with other artifacts required by the OS to start its operation. Toradex System on Modules running Torizon OS as their OS employ U-Boot as bootloader.

Bootloader, OS and applications are usually first installed on a device in a production line as described in Production Programming in Torizon. Toradex also provides mechanisms to allow the update of any of these components after the device is out in the field, something that is made possible by means of the Torizon Cloud update features.

While updating the OS or the application in the field is a common and even recommended operation (for example to keep the system free of security vulnerabilities), updating the bootloader is not usually required nor recommended unless strictly needed; this is because such an operation is generally deemed more risky in that some failures might leave a device in a state where recovery could require physically accessing it.

danger

Bootloader updates are not usually recommended—do it only when strictly needed.

Why Update the Bootloader​

Despite the reservations against it, there are legitimate reasons one might need to update the bootloader, e.g.:

  • When upgrading to a version of Torizon OS requiring a new bootloader: this would be a situation well advertised by Toradex and only expected to happen upon switches of the major version of the OS.
  • When some feature provided within the bootloader is required by the customer: this could happen upon any release of Torizon OS but, again, it would be advertised as part of the OS release documentation.
  • A security vulnerability in the Bootloader affecting the security of the system

Both situations are expected to be rare, but it is worth explaining why they are even possible to occur. The main reason is that the bootloader binary sometimes contains more than the just the code to load the operating system. For example, devices based on the i.MX 8 SoC have a bootloader binary that is actually a container holding multiple pieces of firmware and/or configuration data such as FDR memory timings, the System Controller Unit (SCU) firmware, the ARM Trusted Firmware (ATF) and any potential Cortex-M4 auxiliary firmware. When any of these are updated they may add new capability and/or improve existing low-level capability to be leveraged by the OS.

Disclaimer​

Not all risks of bootloader updates are mitigated by the Torizon Bootloader Update feature. The pros of keeping Torizon OS up-to-date with the latest software outweigh the risks described in the How to Use Bootloader Updates with Torizon OS article.

Toradex specifically recommends when and why to perform a bootloader update. While you are encouraged to perform the updates when recommended by Toradex, you are also encouraged to do so only when strictly required.

Next Steps​

To learn how to perform bootloader updates with Torizon, read the dedicated guide about bootloader updates:

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