A change proposal has been cleared by the Fedora Engineering and Steering Committee “FESCo” for providing a nice out-of-the-box experience for Windows on ARM laptops namely the recent Snapdragon X1 laptops and will also be important for the upcoming Snapdragon X2 laptops too.
Hans de Goede who left Red Hat last year and joined Qualcomm is the one leading this Fedora 44 improvement to provide automatic DTB selection for AArch64 EFI systems. The intent is on making Fedora Live AArch64 ISOs work out-of-the-box for Windows on ARM laptops by automatically handling the right Device Tree at boot time.
The change proposal explains their plans for enhancing the Windows on ARM (Snapdragon X) laptop experience with Fedora 44:
“This change will use a modified kernel image which embeds the systemd-stub boot stub, hardware-id to DTB mappings and relevant DTB files. The systemd-stub will use the embedded mappings to find the right DTB file and automatically load that DTB file. Whereas before users would need to modify the ISO image to manually add the right DTB file, otherwise the image would not work.
The modified kernel image is in essence an incomplete UKI containing just the systemd-stub and the DTBs, but not an initrd nor a kernel commandline. The host generated initrd and host specific commandline will still be supplied by GRUB as usual, including allowing the user to make changes to the commandline through GRUB.
The embedded stub and DTBs cause the vmlinuz size to increase by approx. 3MB from ~16MB to ~19MB.
The main reason for making this change is to allow the prolific Windows on ARM laptop models boot Fedora OOTB.”
FESCo has approved this change to proceed for the current Fedora 44 cycle for enhancing the Fedora Linux on AArch64 laptop experience. Great to see this happen and can’t wait to look at Ubuntu 26.04 vs. Fedora 44 on Snapdragon X Elite.
