Using U-Boot on Raspberry Pi 5 with the Yocto Project and OpenEmbedded

Using U-Boot on Raspberry Pi 5 with Yocto and OpenEmbedded

If you are working with the Yocto Project and OpenEmbedded on the Raspberry Pi 5, switching to the open-source U-Boot bootloader can enhance your setup. In this post, we will walk you through the steps to achieve this using the Yocto LTS release Scarthgap and the community-driven meta-raspberrypi BSP layer.

What is U-Boot?

U-Boot (Das U-Boot) is an open-source bootloader widely used in embedded systems to initialize hardware and load the operating system kernel. Supporting multiple architectures like ARM, x86, and RISC-V, U-Boot offers features such as networking, storage access, and scripting capabilities for system configuration. Its flexibility and broad hardware support make it a preferred choice for Linux-based embedded devices.

How Does It Work on Raspberry Pi 5?

The Scarthgap Yocto release includes U-Boot v2024.01 by default. However, Raspberry Pi 5 support was only introduced in U-Boot v2024.04. To bridge this gap, we will use the scarthgap/u-boot branch of the layer meta-lts-mixins. Follow the steps below to switch to U-Boot on your Raspberry Pi 5.

Steps to Enable U-Boot on Raspberry Pi 5

• Download meta-lts-mixins:

git clone -b scarthgap/u-boot git://git.yoctoproject.org/meta-lts-mixins

• Initialize the build environment:

source oe-init-build-env

• Add meta-lts-mixins to bblayers.conf:

bitbake-layers add-layer ../meta-lts-mixins

• Enable U-Boot in your build by adding the following line to conf/local.conf:

RPI_USE_U_BOOT = "1"

• Build the image:

bitbake core-image-base

• Flash the built image onto a microSD card and boot your Raspberry Pi 5:

Once the build is complete, flash core-image-base to a microSD card and boot your Raspberry Pi 5 to start using U-Boot!

Conclusion

With these steps, you have successfully enabled U-Boot on your Raspberry Pi 5 using the Yocto Project and OpenEmbedded. This setup allows for more flexibility in boot configuration and better support for embedded applications. Happy hacking with U-Boot and Yocto!