Introduction to Embedded Linux Part 3 - Flash SD Card and Boot Process | Digi-Key Electronics

Linux is a powerful operating system that can be compiled for a number of platforms and architectures. One of the biggest draws is its ability to be customized for an application. Tools like Buildroot, OpenWRT, and Yocto Project help us create custom Linux distributions for embedded systems.
In this video series, we will explore Buildroot and the Yocto Project. We also demonstrate how you might develop applications for embedded Linux. We will not dive into the specifics of how each of these systems work but give you a good starting place so you can read or watch more advanced material about working with embedded Linux.
See this written tutorial if you would like to review the commands issued in this tutorial for the Yocto Project: www.digikey.co...
In the previous episode ( • Introduction to Embedd... ), we generated a custom Linux image using the Yocto Project for the STM32MP157D-DK1.
In this episode, we look at how a boot chain works in order to begin running the Linux kernel. We then examine the output of the Yocto Project build process to find which image files are required to create a successful boot chain. For this project, we will use the TF-A trusted boot from Arm as the first stage bootloader, and we will use U-Boot as the second stage bootloader.
The hardcoded ROM bootloader first executes the first stage bootloader (FSBL), which configures the clocks, DDR memory, and loads the second stage bootloader (SSBL). The second stage bootloader configures any necessary peripherals (e.g. networking, USB, display drivers) and begins execution of the kernel. The kernel mounts the root filesystem (rootfs) and executes the processes required to run Linux.
You can read more about ST’s boot chain process in this presentation: www.st.com/con...
We format an SD card with the necessary partitions and flash the image files to those partitions. We then plug the SD card into our STM32MP157D-DK1 and boot into Linux.
The ST tool for flashing SD cards (or other memory) with OS images is the STM32CubeProgrammer, which you can read about here: wiki.st.com/st...
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