Silverletter

A love letter to 'old' hardware, delivered as a bootc image

Silverletter is a bootable container made specifically for the Intel MacBook Air, based on Fedora Silverblue. It currently tracks Fedora 44.

Instead of relegating my 11-year-old, 11-inch laptop to the gap in my couch - I wanted a reliable, modern and secure system with all necessary drivers included, kept close to its upstream base, and carefully tuned to maximise battery life*.

This began as a playground for bootc using the excellent Universal Blue image-template. It became my daily driver in early 2026 and eventually felt worth sharing.

What's in this image - credits to the maintainers of these projects

• A mostly stock Fedora Silverblue experience using Universal Blue's silverblue-main base image
• Broadcom Wi-Fi from Universal Blue akmods, plus the FaceTime HD driver and firmware extractor
• Thunderbolt power tuning*, PCIe ASPM tuning, firmware compatibility tweaks, PowerTOP tuning, Wi-Fi power saving enable by default
• A smaller, hardware-focused initramfs that reduced boot time from ~40 to ~25 seconds on my machine. The initramfs in silverblue-main is ~230MB+ whereas this image's initramfs is ~75MB. Since updates occur on restart, I figured the faster boot was worth pursuing.
• mbpfan for MacBook fan control
• uupd automatic system and Flatpak updates, with restart notifications using uupd Indicator
• GNOME extensions installed and enabled system-wide: AppIndicator and KStatusNotifierItem Support, Xremap, Vitals, User Themes, Dash to Dock,
• Thunderbolt* can be enabled or disabled via tray icon

Optional items

• macOS style keyboard remapping provided by Toshy
• macOS inspired desktop and Firefox theming from WhiteSur GTK, Shell, and GDM styling
• Setup app that adds/removes these items and can restore the default GNOME Flatpak apps from Flathub aswell as replace existing ones with Flathub counterparts (The upstream image exchanges the Fedora flatpak repo for Flathub's)

Screenshot

Hardware compatibility

The image is developed and daily-tested on a 2015 11" MacBook Air (MacBookAir7,1). Its initramfs and power configuration are intentionally tailored to this generation.

Do not assume that other MacBook or MacBook Pro computers are compatible. The trimmed initramfs omits drivers and storage features this specific machine does not need.

These related Intel-based MacBook Air computers are reasonable candidates, but are untested unless stated otherwise:

Model identifier	Apple model	Confidence
MacBookAir7,1	11-inch, Early 2015	Daily-tested target
MacBookAir7,2	13-inch, Early 2015 or 2017	Closest sibling; likely candidate
MacBookAir6,1	11-inch, Mid 2013 or Early 2014	Similar generation; untested
MacBookAir6,2	13-inch, Mid 2013 or Early 2014	Similar generation; untested
MacBookAir5,1	11-inch, Mid 2012	Earlier related hardware; least certain
MacBookAir5,2	13-inch, Mid 2012	Earlier related chassis; least certain

*Battery

One of my primary goals was to maximise battery life - this image includes a number of optimisations to help in this regard. My 11" machine draws around 4–4.5 W which equates to ~10 hours of battery life (50% display brightness with Wi-Fi enabled and no apps running).
With auto-brightness off and brightness at minimum, power usage diops to 3.3–3.5 W (Not that I use my machine this way, just for reference)

An unnecessary power draw on this hardware is unused Thunderbolt controllers

Important

Thunderbolt is intentionally disabled by default to save power. If you rely on that port on the daily, this image is probably not for you. I hardly use mine, so the multiple watts—and hours—of power savings are worth it.

Thunderbolt can be temporarily enabled via the included GNOME extension - however it's experimental and will be disabled again at suspend/reboot.

This re-enablement has been tested with an Apple Thunderbolt to Gigabit Ethernet Adapter; other Thunderbolt devices may work but are not guaranteed.

Power saving audit

There is an included power-audit script which can check if all power saving features are enabled or not:

sudo power-audit.sh

Switch from another bootc/rpm-ostree system

If you already run a bootc-managed system, inspect its current state first:

sudo bootc status

Then switch to Silverletter and reboot into the new deployment:

sudo bootc switch ghcr.io/networkoctopus/silverletter:latest
sudo systemctl reboot

After rebooting, verify the booted image:

sudo bootc status

If the new deployment does not suit your machine, boot the previous deployment from the boot menu or roll back:

sudo bootc rollback
sudo systemctl reboot

Install with the Anaconda ISO

The installer ISO is built weekly. Open the Build disk images workflow, select the newest successful scheduled run, and download the artifact from the Artifacts section at the bottom of the run page. Extract the archive to get the Anaconda ISO, then write it to a USB drive with your preferred image writer.

Note: GitHub requires you to be signed in to download workflow artifacts.

Caution

Installing will erase the selected disk/partition. Back up anything important and carefully confirm the target drive in Anaconda.

Updating

The latest image is rebuilt after pushes and twice weekly, every Wednesday and Sunday.

uupd checks for and stages system and Flatpak updates automatically. The panel indicator shows update activity and tells you when a reboot is needed to enter the staged deployment. GNOME Software updates are disabled because uupd handles them.

Disclaimer

Have fun, but there are no warranties. This personal project is shared in the hope that it is useful. It has only been validated on the test machine, and may fail to boot or work correctly elsewhere. Keep backups and know how to select an earlier deployment before experimenting.

Silverletter is not provided or supported by Apple, Intel, Red Hat, the Fedora Project, Universal Blue, or the Asahi Linux project. Official Fedora software is available from the Fedora Project.

Apple, Mac, MacBook Air, MacBook Pro, macOS, and Apple silicon are trademarks of Apple Inc. Intel and Thunderbolt are trademarks of Intel Corporation or its subsidiaries. Fedora is a trademark of Red Hat, Inc. Linux® is the registered trademark of Linus Torvalds in the U.S. and other countries.

Experimental Apple silicon build using Fedora Asahi Remix

I liked using the above for my 'old' hardware I decided to try it out on my 'new' M2 machine. It's being tested using the experimental and unofficial base image from Fedora Asahi Remix Atomic Silverblue image. The build shares the desktop customisations without applying the power optimisation of the Intel variant.

The image is published separately as:

ghcr.io/networkoctopus/silverletter-asahi:testing