With the Ubuntu 25.10 release in October they are aiming to have a better ARM64 experience with their generic desktop ISO thanks to a new improvement they have been working on called Stubble.
Due to the ongoing mess around ARM desktop/laptop hardware support being primarily reliant on Device Trees rather than ACPI discovery, Ubuntu 25.10 and later will use a new software project they have been working on called Stubble. Stubble is a DTB-loading kernel stub developed by Canonical. This minimal UEFI kernel boot stub is for loading machine-specific Device Trees embedded within a kernel image. The canonical/stubble repository explains:
“A minimal UEFI kernel boot stub that serves a single purpose:
Loading machine specific device trees embedded within a kernel image.
stubble is compatible with systemd-stub(7) and ukify(1). It is designed to seamlessly integrate with Ubuntu’s current bootloader and boot security model. The resulting kernel image can be signed and verified and loaded by grub like any other kernel.
Before loading the kernel, the stub generates hwids of the running machine derived from smbios and compares them to an embedded lookup table in the .hwids section of the kernel image. If a match is found it loads the corresponding device tree from the .dtbauto section before jumping tothe bundled kernel.”
Stubble is already in use by Ubuntu Concept images for the Snapdragon X laptops.
More information on Stubble and the ARM64 desktop ISO improvements for the upcoming Ubuntu 25.10 release can be found via today’s post on Ubuntu Discourse going over this important enhancement.
Update: Trying out the newest Ubuntu 25.10 ARM64 desktop ISO as of today on the Acer Swift Snapdragon X1E laptop… Unfortunately, boot failure with the DT not present:
