
Patching Unpatchable Files
- Anna-Lena Marx
- Embedded , Conferences
- December 5, 2024
In the Yocto world, the .bbappend file is a well-known and documented mechanism for altering recipe files, and an essential part of daily operations. While not common, there are instances where it becomes necessary to modify other file types, such as .inc or .bbclass, which do not offer an equivalent append mechanism. This session will summarize various strategies for effectively handling these file types when patching cannot be avoided.
In my recent presentation at the Yocto Developer Day in Vienna, I mentioned using the KAS patch mechanism for minor modifications to files like .inc or .bbclass, where the Yocto internal overwriting mechanism via .bbappend files does not apply. Initially intended as a helpful side note on how I navigated a few unique situations, this part quickly escalated into the most discussed segment of the talk. Half of the attendees I spoke with found it valuable, while the other half expressed strong objections.
In this follow-up session, I aim to dive deeper into the complexities of working with these “unpatchable” files and explore the following key questions:
In which situations is patching valid? What strategies and approaches —both well-known and lesser-known— are generally available? Which strategy is best suited for different scenarios and use cases? In conclusion, this talk aims to present and document various strategies for addressing the challenge of “patching unpatchable files” and to encourage discussions on best practices.
Presented at
- Yocto Project Summit 2024.12, virtual
Related Posts

Yocto on the Edge - Unusual challenges when building not so embedded systems
- Anna-Lena Marx
- October 8, 2024
- Embedded , Conferences
Building embedded systems with Yocto on ARM platforms is a common practice, but when the products move further to the edge and become less “embedded,” new challenges arise. In this session, we will explore the requirements and challenges faced when developing Yocto-based systems for edge computing based on Intel.
We will dive into topics such as provisioning x86-based platforms, securely managing Linux user logins on a read-only root file system with enforced password changes, and implementing A/B updates together with secure boot. Real-world project requirements will be used as a guide to discuss practical solutions and best practices for addressing these challenges.
Read Post
USB Updates - Challenges, Approaches and Practical Tips
- Anna-Lena Marx
- February 24, 2024
- Embedded , Conferences
Over-the-air updates have established themselves as the standard for networked devices, but the effort involved in operating the server side is not always commensurate with the benefits. In such cases, the supposedly simple and quick solution of implementing updates via USB is often chosen. But is it really always that uncomplicated? What considerations are necessary to implement USB updates effectively?
This presentation provides an insight into the challenges of USB updates and presents solutions and practical tips for successful implementation. Find out which aspects need to be considered in order to optimize USB updates and ensure a smooth process
Read Post
LoRaWAN in theory and practice: A trip through Munich
- Anna-Lena Marx
- February 24, 2024
- Embedded , Conferences
LoRaWAN (Long Range Wide Area Network) is becoming increasingly popular, thanks in part to public networks such as The Things Network, which allow users to dispense with their own gateways. LoRaWAN also promises potential in terms of range and energy efficiency. But how does the standard perform in practice?
The aim of the presentation is to shed light on the technical background and demonstrate how practicable LoRa is in the field using real tests. It will be shown how the standard behaves in urban and rural areas, how differences in height of the gateway and different antennas influence the transmission quality.
Read Post