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Snowfield

Snowfield is Frostyard’s GNOME desktop for Microsoft Surface devices. It is a Debian Trixie bootc/composefs image for x86-64 machines with UEFI, built from the same Base as the other Frostyard images. It has the Snow desktop and the linux-surface kernel.

Snowfield is untested on representative Surface hardware. Its hardware gate was waived for catalog inclusion, not passed.

The system lives in a read-only /usr that updates as one piece, and you can roll back to the previous version. Image and system-extension applications live under /usr. Your homes, Flatpak data, containers, and update state live under /var.

Install

Section titled “Install”

Firn is the installer. It needs UEFI and erases the disk you pick. It works with or without Secure Boot, TPM 2.0, and disk encryption, and asks you about each one. Use a disk of at least 30 GiB, and more if you plan to keep Flatpaks, containers, and several updates. The installer runs from RAM and needs at least 4.5 GiB of memory.

  1. Download the installer and its checksums:
  2. Check the signing key’s fingerprint and the ISO, then write the ISO to a USB stick. The installation guide has the exact gpgv and sha256sum commands and the commands to write the stick. Read its warning on picking the right device.
  3. Boot the stick. In Firn, pick the bootc Snowfield product, review the recipe Firn builds, and confirm the exact target disk.
  4. If Firn shows a recovery key, store it somewhere other than this disk before you continue.
  5. If Secure Boot is on, enroll the MOK when asked. Without it, the MOK-signed boot stage is not trusted while Secure Boot is enforced. Snowfield needs no other key: the linux-surface kernel boots inside the Frostyard-signed image.

The native in the ISO address is an old folder name. It does not mean an A/B install.

First boot

Section titled “First boot”

Log in at the GDM screen with the user you created in Firn. Snowfield has the same desktop as Snow, so the Snow page covers the session. Firn can install the chosen core Flatpak set as part of the recipe; Snowfield uses Snow’s list. The image carries the list at /usr/share/frostyard/snowfield.core-flatpaks.json. If yours included it, the apps are already there.

Check that the system is healthy:

Terminal window
systemctl is-system-running
sudo bootc status
sudo snosi-update-status --check
systemctl list-timers bootc-update-stage.timer

bootc status shows the booted and staged deployments, and names the image it follows. If it shows null instead, see Troubleshooting. snosi-update-status --check tells you whether a newer image is published. The timer is listed with its next run.

Install applications as Flatpaks or as system extensions. Do not install APT packages into /usr: an image update does not keep them. The package lists in the build are not a package manager you can add to.

Updates and rollback

Section titled “Updates and rollback”

Updates are automatic. Every hour, bootc-update-stage.timer checks for a new image, pulls it with Podman, and stages it. The timer adds a random delay of up to 15 minutes. The new version starts at your next normal reboot. The stager does not force a reboot.

Enabled system extensions update on their own. A new version is staged and starts at the next boot. See Automatic updates.

The stager runs the bootc commands itself. You do not need to run them. On the first staged update, while the host does not yet follow the image from containers-storage, it runs bootc switch --transport containers-storage. From then on, in steady state, it runs bootc upgrade, because a second bootc switch to the same image would do nothing. Both paths verify the staged digest before they report success.

To go back to the previous version:

Terminal window
sudo bootc rollback
sudo systemctl reboot

Homes and container data in /var are shared by all versions, so a rollback keeps them. After a rollback, the updater does not stage the version you rolled back from again. It waits for the next published image.

Keep about twice the image size free in /var. The updater pulls each new image into /var before it stages it.

What ships

Section titled “What ships”

Snowfield is Base plus the bootc runtime, the bootc security setup, Snow’s desktop composition, the linux-surface kernel, and the image output format.

Layer What you get
Base Debian Trixie userspace, systemd, the hourly update stager, Updex, and the system-extension definitions
Bootc runtime bootc, libostree-1-1, and the packages OCI bootc needs
Desktop Snow’s GNOME desktop: GNOME Shell, GDM, Nautilus, Ptyxis, PipeWire, CUPS, Flatpak, and the desktop integration packages
Kernel linux-image-surface, linux-headers-surface, libwacom-surface, and iptsd
Core Flatpak set Snow’s list: the Bazaar App Store, MissionCenter, Extension Manager, DistroShelf, and a set of GNOME apps
Containers Podman and Distrobox, plus systemd-container and the Frostyard Intune integration

The table shows the main layers only. Snowfield reuses Snow’s composition, so it also carries Homebrew integration, frostyard-chairlift, snow-first-setup, the Snow Plymouth theme, the hotedge and Logo Menu GNOME extensions, and the Bazaar companion build. The Snow page lists them.

The Surface kernel

Section titled “The Surface kernel”

Snowfield swaps Snow’s kernel for the Surface kernel. Its extra packages are linux-image-surface, linux-headers-surface, libwacom-surface, and iptsd.

The Surface packages come from the linux-surface Debian repository at https://pkg.surfacelinux.com/debian: suite release, component main, architecture amd64, signed by the linux-surface keyring.

The rest of the hardware stack is the same as Snow’s. Most firmware and Mesa come from trixie-backports, which is pinned at priority 100. The kernel fragment also lists a few firmware packages with no pin, such as firmware-linux-free, atmel-firmware, and bluez-firmware. If you build Snowfield yourself, do not add unpinned copies of the pinned packages to the package list.

Choose Snowfield

Section titled “Choose Snowfield”

Choose Snowfield for a Microsoft Surface device when you want the Snow desktop on it. For the same desktop on other hardware, use Snow. The other products are:

  • Snow: the general-purpose GNOME desktop.
  • Sundog: KDE Plasma, bootc only.
  • Floe: a headless server.

Base is the shared foundation, not a fifth installer choice. Snowfield has the Trixie userspace with the Surface kernel.

Troubleshooting

Section titled “Troubleshooting”
Symptom Check Fix
bootc status shows spec.image: null The host is not managed by bootc. It is most likely an old nbc or native A/B install. See Moving from an nbc or A/B install.
No update is staged systemctl list-timers bootc-update-stage.timer and journalctl -u bootc-update-stage.service Wait for the hourly run. Check the network and the free space in /var.
Staging fails for lack of space Compare the free space in /var with the image size Free space or grow the disk. The updater needs room for the download, the new version, and the previous one.
Secure Boot or TPM does not behave as you expect bootc status and the firmware settings Check the firmware settings, then read the Bootc Secure Operations runbook. Secure Boot is not production-ready yet.

Moving from an nbc or A/B install

Section titled “Moving from an nbc or A/B install”

Old nbc and native A/B installs get no new images or updates after 2026-09-30. There is no in-place conversion. Back up, install fresh with Firn, and restore your data.

The migration runbook lists what to save: your /etc changes, homes, Podman volumes, and /var/lib/tailscale if you use Tailscale. Check the backup from another machine before you erase the disk.

See also

Section titled “See also”

Sources

Section titled “Sources”

Reviewed 2026-10-27 against snosi commit b2858ca0222814c395cf8248db98f3e096d57dc9.