Canonical has officially restarted development on Ubuntu Core Desktop, breathing new life into an immutable, snap-based take on the flagship Linux distribution that had sat dormant following an initial developer preview in 2023. Jon Seager, Canonical’s Vice President of Engineering for Ubuntu, confirmed that a dedicated engineering team is now actively working on the project, with the long-term objective of allowing it to grow into the default Ubuntu desktop experience as the technology matures.
For current users, traditional installations of Ubuntu Desktop are not changing, and Canonical has emphasized that the various official Ubuntu flavors are under no pressure to build Core versions of their own. Alongside the resurrection of Core Desktop, Canonical engineer Juerg Haefliger has proposed a separate firmware packaging strategy for Ubuntu Long Term Support (LTS) releases designed to shield older, general availability kernels from firmware written exclusively for newer hardware enablement kernels. Both initiatives are currently in early stages of development, meaning details and implementation specifics remain subject to change as engineering cycles progress.
The concept of Ubuntu Core itself is not new. Originally launched in 2014, Ubuntu Core serves as Canonical’s hardened, highly secure operating system designed for Internet of Things and embedded devices at scale. It relies on an immutable architecture with strict confinement. In this model, the operating system kernel, the base system image, and individual applications are kept entirely separate and updated independently of one another, significantly reducing the attack surface and making the system far more resilient against catastrophic software failures.
When applied to the desktop paradigm, Ubuntu Core takes the immutability framework a step further. On Ubuntu Core Desktop, virtually every system component is packaged as a Snap package, spanning everything from the bootloader and the system kernel down to the desktop environment itself and everyday user applications. This modular design makes the underlying system drastically harder to break and considerably easier to recover if something goes wrong.
The initial developer preview released in 2023 ultimately fell short of expectations because it attempted to package too many foundational desktop components—including the GNOME desktop environment and its display manager login screen—into a single, bulky Snap package. Learning from that experience, the new engineering approach focuses on decoupling these pieces, ensuring that the desktop environment and core system components are cleanly separated into their own distinct packages.
A newly assigned team of developers has already made tangible progress migrating the architecture of the old preview onto the newer Core 26 base. Infrastructure required to support automated daily image builds is expected to be finalized within the coming weeks, and the core development work is scheduled to run continuously through the Ubuntu 27.04 release cycle.
Despite the promising technical direction, applications remain a significant hurdle for the project. Because Ubuntu Core Desktop operates strictly on confined Snaps, traditional classic desktop applications such as Visual Studio Code cannot run directly within the environment without modification. To bridge this gap, Jon Seager’s preferred architectural vision is to host such legacy applications within Workshop, Canonical’s sandboxed development environment, and project their graphical windows onto the main desktop interface.
Furthermore, fine-grained permission prompting is considered a critical requirement for Core Desktop’s ultimate success. Under this security model, the operating system would actively prompt users for explicit authorization before a confined application attempts to access sensitive system resources, such as the webcam, microphone, or the user’s private home directory.
What’s the firmware proposal about?
In a parallel engineering effort that targets stability across mainstream deployments, Canonical engineer Juerg Haefliger has proposed introducing a dedicated firmware package for Ubuntu LTS releases to prevent firmware regressions on older kernels. Standard Ubuntu LTS releases traditionally launch with a single initial kernel, known as the general availability kernel, while the hardware enablement stack subsequently rolls out newer, advanced kernels for that exact same release over time.
For instance, Ubuntu 24.04 launched originally running kernel 6.8, while its current hardware enablement kernel has advanced to version 7.0. Standard desktop installations of Ubuntu 24.04 follow the hardware enablement path by default, whereas server installations typically remain on the general availability kernel unless administrators explicitly opt into newer options. Under the current system architecture, both kernels share a single, unified firmware package. This means that firmware updates backported to accommodate newer hardware enablement kernels are automatically pushed down to general availability systems as well.
The core issue, as Juerg Haefliger points out, is that hardware vendors rarely test older general availability kernels against newly introduced firmware updates. He highlighted specific AMD regression bugs on general availability systems that surfaced following recent backports in Ubuntu 24.04.
To resolve this systemic risk, his proposed solution involves creating a dedicated firmware package that hardware enablement kernels would explicitly depend upon. This package would carry the complete, unedited set of firmware files originating from the specific Ubuntu release associated with the hardware enablement kernel, rather than relying on a small handful of hand-picked files backported into the older LTS release.
Under this proposed model, general availability systems would remain anchored to the regular, tested firmware branch, and the two differing sets of firmware would not be permitted to coexist on the same machine. A machine utilizing both kernels would automatically load the hardware enablement firmware even when booting into the general availability kernel. The bug report tracking this change currently leaves the proposed workaround open for consideration, and while it is being actively tracked against the upcoming Ubuntu 27.04 release—codenamed "Tenacious T-Rex" and scheduled for April next year—the proposal is still fresh, lacks a formal assignee, and has an open test case section marked to be determined.
Neither the restart of Ubuntu Core Desktop nor the firmware isolation proposal impacts regular users on standard Ubuntu installations at this moment. However, as automated daily images for Core Desktop begin materializing in the near future, the Linux community will get its first clear look at how far Canonical can push the boundaries of an immutable desktop operating system.
