[ER2026] rsinit -- a tiny initramfs toolbox for embedded systems (Michael Olbrich)

Traditionally, embedded systems were simple enough that an initramfs was not needed at all. This has changed in the last recent years with new requirements, often related to verified boot. That means that additional steps are now needed before the rootfs can be mounted. Existing solutions, such as the Yocto initramfs-framework have significant drawbacks. The resulting initramfs is quite big (multiple megabytes) which has a noticeable impact on the boot time. And while the shell scripts make it easy to customize, robust error handling is difficult. In this talk, Michael will introduce rsinit, a single-binary-initramfs for embedded systems, written entirely in Rust. It is tiny (less than 200 KiB), very fast and "just works" for simple use-cases. Alternatively, it can be uses as a library to build a fully custom binary. Beyond being small, it brings the full power of Rust to the initramfs, which allows building additional features (such as splash screens or read-ahead) without pulling in further dependencies. Michael will present the existing features, explain the design choices and give an overview of what is planed for the future. Slides available at: https://embedded-recipes.org/2026/sch...