Stay updated with the latest U-Boot development news, features, tutorials, and community highlights.
U-Boot Concept now supports the EFI Boot Graphics Resource Table (BGRT) feature. This enhancement allows for a more seamless and branded boot experience on devices that use EFI_LOADER, i.e. the Unified Extensible Firmware Interface (UEFI). What is BGRT? The BGRT is a table in the ACPI (Advanced Configuration and Power Interface) that allows the firmware […]
What is virtio-fs? For those unfamiliar, virtio-fs is a modern shared filesystem designed specifically for virtualised environments. It allows a virtual machine (the “guest”) to access a directory on the host system, but it does so with a focus on performance and providing local filesystem semantics. Unlike traditional methods like network filesystems (e.g., NFS, Samba) […]
U-Boot makes extensive use of linker-generated lists to discover everything from drivers to commands at runtime. This clever mechanism allows developers to add new features with a single macro, and the linker automatically assembles them into a contiguous array. The C code can then iterate through this array by finding its start and end markers, […]
In the world of software development, consistency is key. A recent update to U-Boot Concept takes a solid step in that direction by restructuring how it handles emulation targets. This change makes life easier for developers working across different processor architectures. Previously there were inconsistencies in the configuration system (Kconfig). For example, enabling QEMU emulation […]
U-Boot supports a fairly wide variety of filesystems, including ext4, ubifs, fat, exfat, zfs, btrfs. These are an important part of bootloader functionality, since reading files from bare partitions or disk offsets is neither scalable nor convenient. The filesystem API is functional but could use an overhaul. The main interface is in fs/fs.c, which looks […]
VBE has been a long-running project to create a smaller and faster alternative to EFI. It was originally introduced as a concept in 2022, along with a sandbox implementation and a simple firmware updater for fwupd. In the intervening period an enormous about of effort has gone into getting this landed in U-Boot for a […]
A few weeks ago I took a look at Qboot, a minimal x86 firmware for QEMU which can boot in milliseconds. Qboot was written by Paolo Bonzini and dates from 2015 and there is an LWN article with the original announcement. I tried it on my machine and it booted in QEMU (with kvm) in […]
Welcome to the new official blog for Das U-Boot! For over two decades, the U-Boot mailing list has been the vibrant hub of our development discussions. While the mailing list remains our primary channel for patches and technical conversations, this blog will serve as a new platform to share deeper insights, project news, and community […]
U-Boot makes extensive use of linker-generated lists to discover everything from drivers to commands at runtime. This clever mechanism allows developers to add new features with a single macro, and the linker automatically assembles them into a contiguous array. The C code can then iterate through this array by finding its start and end markers, which are also provided by the linker. For this to work, there’s a critical assumption: the array of structs is perfectly contiguous, with each element having the exact same size. But what happens when the linker, in its quest for optimisation, breaks this assumption? A Little Wrinkle We have known for a while about a subtle issue where the linker, in certain cases, would insert a few bytes of padding between elements in these lists. This is usually done to align the next element to a more efficient memory boundary (like 8 or 16 bytes). […]
What is virtio-fs? For those unfamiliar, virtio-fs is a modern shared filesystem designed specifically for virtualised environments. It allows a virtual machine (the “guest”) to access a directory on the host system, but it does so with a focus on performance and providing local filesystem semantics. Unlike traditional methods like network filesystems (e.g., NFS, Samba) or even the older virtio-9p protocol, virtio-fs is engineered to take advantage of the fact that the guest and host are running on the same machine. By leveraging shared memory and a design based on FUSE (Filesystem in Userspace), it bypasses much of the communication overhead that can slow down other solutions. The result is a faster, more seamless file sharing experience that is ideal for development, testing, and booting from a root filesystem located on the host. virtio-fs arrives in U-Boot Concept The recent merge request in U-Boot Concept introduces a new virtio-fs driver […]
U-Boot Concept now supports the EFI Boot Graphics Resource Table (BGRT) feature. This enhancement allows for a more seamless and branded boot experience on devices that use EFI_LOADER, i.e. the Unified Extensible Firmware Interface (UEFI). What is BGRT? The BGRT is a table in the ACPI (Advanced Configuration and Power Interface) that allows the firmware to pass a logo or image to the operating system during the boot process. This means that instead of a generic boot screen, users can be greeted with a custom logo, such as a company or product brand. This creates a more professional and polished user experience. Why is this important for U-Boot? By supporting BGRT, U-Boot can now provide a more consistent and visually appealing boot experience on a wider range of devices, particularly those running operating systems like Windows or Linux that support UEFI. This is especially valuable in embedded systems and custom […]
