Rootcommit WIP

Board Bring-Up: Radxa Dragon Q6A with Mainline Linux and Yocto

Sat, 18 Apr 2026 00:00:00 +0000

Radxa Dragon 6A

The Radxa Dragon Q6A is a credit card-sized single-board computer built around Qualcomm’s QCS6490 — the same silicon family found in the Fairphone 5 and Qualcomm’s own RB3gen2 reference platform. It packs an octa-core Kryo 670 CPU, an Adreno 643 GPU, and a 12 TOPS Hexagon NPU into a board with Gigabit Ethernet, WiFi 6, HDMI, triple camera connectors, and an M.2 NVMe slot. Starting at around $60, it sits in an interesting spot — significantly more compute per dollar than a Raspberry Pi 5, with a genuine ML inference pipeline that doesn’t require an external accelerator. Qualcomm provides Yocto builds for RB3Gen2 boards and Radxa mentions this in their documentation but doesn’t provide any how-to. In this article, we shall explore the steps taken to get Yocto running with Mainline Linux Kernel.

Wed, 15 Apr 2026 00:00:00 +0000

U-Boot: protect sensitive environment variables

Wed, 15 Apr 2026 00:00:00 +0000

This is a follow-up from our Accessing the U-Boot environment from a C program blog post.

🌳Need to protect the environment

When you’re trying to harden an embedded Linux device to make it more resistant to attacks, one key part to secure is the bootloader, because that’s the part that boots the operating system. Even you implement a secure boot chain, if an attacker manages to interrupt the boot process and get access to the bootloader shell, this attacker would be able to load and run her/his own payload on the device.

Tue, 14 Apr 2026 00:00:00 +0000

Mainline Linux 7.0 running on Arduino Q

Mon, 13 Apr 2026 00:00:00 +0000

Here are steps to reproduce it by yourself, if you are the happy owner of this board, currently priced at 48 EUR on the Arduino shop for the 2 GB version. This is done without removing the original kernel. Your board will still boot such kernel by default.

Setup and prerequisites

To do this by yourself, you will need:

An Arduino Q board
A USB-C hub with external power, to power the board and to connect external devices such as USB mass storage or USB-Ethernet.

Thu, 09 Apr 2026 00:00:00 +0000

Accessing the U-Boot environment from a C program

Wed, 08 Apr 2026 00:00:00 +0000

Need to modify the U-Boot environment from Linux

A/B update and recovery workflow implemented for a Root Commit customer

There are multiple reasons for wanting to modify U-Boot variables from Linux, one of them being to implement A/B update mechanisms. Typically, after you’ve flashed a device with a new version, you’ll set the upgrade_available U-Boot variable to 1, reboot, and let U-Boot try to boot the new version.

Embedded Linux Resources

Sun, 01 Mar 2026 00:00:00 +0000

Useful resources for people learning about embedded Linux, or interested in getting the latest updates.

Mobile platforms

Chris Simmonds, David Llewellyn-Jones, Romain Hunault - State on FOSS on Mobile (Video, 2026)
Early 2026 status on Android and other Linux-based operating systems for smartphones

Updates

Jana Perić - OTA Updates in the Wild (Video, PDF, 2025)
A good introduction to all aspects of Over The Air updates.

Yocto Project

Anna-Lena Marx - Managing Long-Term Risk and Compliance in Embedded Linux with Yocto (PDF, 2026)

Thu, 26 Feb 2026 00:00:00 +0000

Thu, 19 Feb 2026 00:00:00 +0000

Contributions to Linux 6.19

Tue, 10 Feb 2026 00:00:00 +0000

Root Commit’s contributions to Linux 6.19

Linux 6.19 is out with 7 contributions from Root Commit:

Mon, 19 Jan 2026 00:00:00 +0000

Sun, 18 Jan 2026 00:00:00 +0000

Tue, 13 Jan 2026 00:00:00 +0000

Mon, 12 Jan 2026 00:00:00 +0000

Tue, 16 Dec 2025 00:00:00 +0000

Mon, 15 Dec 2025 00:00:00 +0000

Mon, 08 Dec 2025 00:00:00 +0000

Yocto Project Virtual Summit 2025: devtool hands-on class slides

Wed, 03 Dec 2025 00:00:00 +0000

Happy to share the slides from my Devtool hands-on class presentation at Yocto Project Virtual Summit 2025.

Devtool is a very helpful tool for creating and maintaining recipes. I’m very happy I accepted to take over the traditional devtool hands-on class at the Yocto Project Summit in 2024, because devtool provided invaluable in my Yocto work since then.

Thanks to the additional experience, a devtool section was added to Root Commit’s Yocto Project and OpenEmbedded training course, and the hands-on slides got a complete overhaul compared to the 2024 version. The 2025 version is also based on the upcoming Whinlatter version, and is also expected to be compatible with the next Wrynose LTS version.

Sat, 29 Nov 2025 00:00:00 +0000

Using Yocto to build images for Orange Pi 3B

Tue, 25 Nov 2025 00:00:00 +0000

Introduction

Orange PI 3B is a cheap and attractive Raspberry Pi sized single board computer based on the Rockchip RK3566:

Rockchip RK3566 (4x ARM Cortex-A55 @ 1.6GHz)
ARM Mali-G52-2EE GPU (OpenGL ES 1.1/2.0/3.0/3.1/3.2, Vulkan 1.1, OpenCL 2.0)
LPDDR4 RAM (2/4/8 GB)
Micro-SD card slot
SPI flash (16/32 MB)
Optional eMMC pluggable module (16/32/64/128/256 GB)
Wi-Fi5 + Bluetooth 5.0, BLE
1x USB 2.0 Type A OTG, 2x USB 2.0 Type A HOST, 1x USB 3.0 Type A Host

Mon, 24 Nov 2025 00:00:00 +0000

Sun, 23 Nov 2025 00:00:00 +0000

Tue, 18 Nov 2025 00:00:00 +0000

Mixing Yocto training and consulting in Italy

Thu, 13 Nov 2025 00:00:00 +0000

Training or consulting?

In partnership with Amarula Solutions, I was in discussion with an Italian company, Novavision. Moving to a new hardware platform, they wanted to take the opportunity to gain ownership of the tools that are used to build their products, here Yocto, instead of subcontracting this part of system development as they did previously.

Their first idea was to order our Yocto Project and OpenEmbedded training course. However, facing project deadline pressure, they also wondered whether consulting wouldn’t be a better choice to get their new project started in an efficient way. However, they didn’t want to fall back to subcontracting what they want to learn. That’s how the idea of a hybrid solution came up: consulting and training at the same time!

Mon, 10 Nov 2025 00:00:00 +0000

Orange Pi RV2 RISC-V board running Linux 6.18-rc1

Thu, 16 Oct 2025 00:00:00 +0000

Introduction

Five days ago, I received the Orange Pi RV2 board I ordered. For about 54 EUR / 64 USD (+ shipping), this board has very attractive features, in particular:

Top view - Source Orange Pi

8 GB of LPDDR4X RAM (2 and 4 GB options exist)

Yocto security: Kernel Hardening

Tue, 07 Oct 2025 00:00:00 +0000

This is another blog post about securing your Yocto built systems:

Introduction

The Linux kernel is the cornerstone and stronghold of a Linux based system. Unlike user-space applications which run with limited privileges, if it’s compromised, there is almost no limit to what an attacker can do.

While nothing is unbreakable, there are two types of settings you can change to make your kernel harder to compromise:

Wed, 01 Oct 2025 00:00:00 +0000

Training Bookmarks

Wed, 01 Oct 2025 00:00:00 +0000

These bookmarks have been created for the participants to our training courses, but are also available for anyone to reuse under the terms of the Creative Commons Attribution-Share Alike 4.0 license.

Printable version (PDF)
Sources
Credits

Yocto bookmark and new training dates

Wed, 01 Oct 2025 00:00:00 +0000

Bookmark

After a brief announcement two weeks ago, here is the new Yocto command reference bookmark, in a format you can print and modify, according to the terms of the Creative Commons Attribution-ShareAlike license.

In particular, the PDF version is ready to be printed. This way you will get 5 bookmarks on double-sided A4 paper.

The documents were created with the Scribus open-source publishing application. It’s a great program to create leaflets, brochures and any professional looking documents. Sources are available in our GitLab repository.

Linux 6.17 is out and already running at Root Commit

Mon, 29 Sep 2025 00:00:00 +0000

Linux 6.17 has just been released, and it’s already running here at Root Commit.

The first system it’s been running on is this Toradex Verdin iMX8M Mini SOM (below the heat sink!) on the Dahlia Carrier board. I’m using this board for a medical device project at the moment.

Here are my notes for building Linux 6.17 for this device:

Get the Linux 6.17 sources (through git or tarball)

Sat, 20 Sep 2025 00:00:00 +0000

Digital hygiene: use USB tethering to connect your laptop

Sun, 14 Sep 2025 00:00:00 +0000

When you are on the go, have you thought about connecting your GNU/Linux PC to the Internet through a USB connection to your phone?

Using open networks is definitely not recommended. Your connection is not encrypted and others could intercept it. If you have no other choice, connecting to the Internet through a Virtual Private Network (VPN) is strongly recommended.
Even using an untrusted WiFi network protected by a password (like in a hotel or in a commercial building) is not fully secure. If the password is shared, other guests could intercept your connection and try to attack your PC. Here, a VPN is recommended too.

Consulting

Thu, 04 Sep 2025 00:00:00 +0000

We are available to support you in our areas of expertise

Yocto Project and OpenEmbedded Getting started (training available too) Review of your implementation: layers and recipes Integration of features and applications Meeting security requirements Migration to supported releases Adding new features to upstream releases	Linux Kernel Getting started (training available too) Device driver and Device Tree code reviews Investigating performance and functional issues Adding new features to upstream kernels Kernel hardening
Embedded Linux Getting started with product development (training available too) Choosing a build system Review of your implementation Embedded Linux security audits Implementing software updates Linux boot time reduction (specific training available too)	Use our contact form to share your requirements with us.

Yocto Security: Production and Development Images

Thu, 04 Sep 2025 00:00:00 +0000

This blog post is part of a series about securing your Yocto built systems:

What to avoid

So, you use Yocto to build an image for your embedded device. You tweak the image and distribution settings to get the features you need, and other developers use the SDK built by Yocto to create and build the User Interface and other applications.

"Securing Yocto Built Systems" presentation slides

Wed, 03 Sep 2025 00:00:00 +0000

Last week, I gave a “Making Yocto Built Images More Secure” presentation at the Embedded Linux Conference in Amsterdam.

The main goal was to share the research I’ve done so far for a customer project, and gather feedback from the audience.

Mon, 21 Jul 2025 00:00:00 +0000

See how U-Boot modifies your board device tree

Mon, 21 Jul 2025 00:00:00 +0000

If you compare the device tree as loaded by Linux, available in /sys/firmware/fdt, you will see that it differs from the one that you loaded in U-Boot. Taking the time to make the comparison is quite instructive.

Let’s do this on my Toradex Verdin iMX8M Mini SoM on the Dahlia carrier board.

Decompiling the DTB

It’s easy to decompile any Device Tree Binary (DTB) file using dtc, the Device Tree Compiler.

Copy /sys/firmware/fdt from your live Linux system to external storage (assuming your external storage is mounted on /mnt/usb)
cp /sys/firmware/fdt /mnt/usb/linux.dtb

Seven steps to grow your embedded Linux skills

Sun, 20 Jul 2025 00:00:00 +0000

A variant of this article also exists as a conference presentation.

Do you already have a job in embedded Linux but wish to be given more challenging goals? Or are you in IT, already using Linux on your own laptop, and dreaming about landing an embedded Linux job, possibly starting as your own boss? Follow my advice in a patient and consistent way, and you will achieve your goals in less than 12 months.

Mon, 07 Jul 2025 00:00:00 +0000

Thu, 03 Jul 2025 00:00:00 +0000

Virtual Packages in Yocto Project / OpenEmbedded

Thu, 03 Jul 2025 00:00:00 +0000

Understanding Virtual Packages in Yocto Project / OpenEmbedded

If you are using Yocto, this post will help you learn about Virtual Packages: how they work, why they are useful, and how to create them step by step.

We assume you are already familiar with:

Yocto Project setup
Basic command of BitBake and recipe syntax

What is a Virtual Package?

Imagine you have multiple implementations of the same functionality (for example, different kernels such as a real-time kernel, a boot-time optimized kernel, and a kernel without loadable modules). Of course, your final image will include only one kernel, but you may want to keep several implementations in your project, so you can switch between them easily whenever you like.

Wed, 02 Jul 2025 00:00:00 +0000

Mon, 19 May 2025 00:00:00 +0000

Fri, 02 May 2025 00:00:00 +0000

Wed, 09 Apr 2025 00:00:00 +0000

Public Training Session Inquiry Form

Wed, 09 Apr 2025 00:00:00 +0000

Interested in joining a Root Commit in-person public session in a convenient location for you?
If so, let us know about the courses you are interested in and your preferred location. If we have enough interested people in the same area, we would be delighted to organize such a session there.

And if you are in a hurry and other co-workers of yours can be interested too, a private session at your employer’s site is also possible! Just ask us.

Tue, 08 Apr 2025 00:00:00 +0000

Access to Matrix chatroom

Mon, 07 Apr 2025 00:00:00 +0000

Introduction

At Root Commit, we use Matrix chatrooms to offer support during practical labs as well as outside course hours. This makes it very easy for you to ask questions, share screenshots (just by pasting into the chat), get help from the instructors and other participants, and learn from everyone’s experience.

The Matrix protocol is also end-to-end encrypted and it will protect the privacy of our conversations, especially in private sessions.

Request access to a Matrix chatroom

Mon, 07 Apr 2025 00:00:00 +0000

[ninja_form id=‘9’]

Yocto: variable overrides tricks

Tue, 18 Mar 2025 00:00:00 +0000

Kernel Recipes conference in Paris
One of the best for Linux kernel topics 😉.
Recommended by Root Commit!

I discovered a intriguing phenomenon while preparing my How to test the latest mainline Linux kernel or bootloader presentation at OpenEmbedded Workshop 2025. It turned out there was something incomplete in my understanding of BitBake variable overrides.

1-day Technical Seminar Request Form