U-Boot has two testing worlds that rarely meet. Python tests are flexible and can set up complex scenarios – disk images, network configurations, boot environments. C tests are fast, debuggable, and run directly on hardware. What if we could combine them? The Problem Consider filesystem testing. You need to: The Python test framework handles steps…
Have you ever seen output like this from your test suite? That’s not a buffer overflow or memory corruption. It’s a wierd interaction between linker alignment, compiler optimisations, and pointer arithmetic. Let me tell you how we tracked it down. The Mystery U-Boot uses ‘linker lists’ extensively – a pattern where the linker collects scattered…
The robust operation of any complex software system, especially one as foundational as U-Boot, hinges on the reliability of its core services. Among these, dynamic memory allocation via malloc() is paramount. While often taken for granted, failures in malloc() can be silent saboteurs, leading to unpredictable behaviour, security vulnerabilities, or outright system crashes. Here, we…
This final series in Concept closes out the complete implementation of TKey hardware-backed full disk encryption (FDE) in U-Boot. The previous series established the core logic and UI flow. This final work wraps up the effort by providing end-to-end testing, a useful Python tool for key management on the host, along with documentation, making the…
A new series in Concept introduces the complete logic and UI enhancements required to use a TKey to unlock an encrypted disk (like a LUKS partition) before booting an operating system. 1. The TKey Unlock Flow The TKey unlock process is complex because it involves iterative communication with the external hardware and handling scenarios like…
A new series just landed, focussed on making one part of U-Boot’s new graphical menus (Expo) considerably better with non-popup menus. A long-standing and annoying limitation in expo is that couldn’t really type into text fields (like for passwords) if the menu wasn’t a pop-up (i.e. as used by the ‘cedit’ configuration editor). Now, with…
For over two decades—since 2002—U-Boot has relied on version 2.6.6 of Doug Lea’s malloc (dlmalloc, old docs) to handle dynamic memory allocation. While reliable, the codebase was showing its age. In a massive 37-patch series, we have finally updated the core allocator to dlmalloc 2.8.6. This update brings modern memory efficiency algorithms, better security checks,…
Debugging embedded bootloaders can often feel like working in the dark. When execution crashes or behaves unexpectedly, the first question an engineer usually asks is, “How did I get here?” Of course, one should always have a JTAG debugger ready to press into service, but so few boards provide a JTAG header. To help, a…
In the world of U-Boot, the Device Model (DM) and Device Tree (DT) are the standard for hardware description. However, U-Boot runs on a massive variety of hardware, including constrained systems where full Device Tree support (OF_REAL) might be disabled. A recent patch cleans up how the core handles these “no-Device-Tree” scenarios, ensuring that code…
U-Boot is a massive project. With thousands of files, nearly endless configuration possibilities, and complex Kconfig dependencies, a single board configuration often only compiles a small fraction of the total source tree. For developers and maintainers, this complexity often leads to difficult questions: Simply searching for CONFIG_ macros or header inclusions is rarely enough. The…
