**BRIMSTONE CORE — R1 DEVELOPMENT UPDATE**
**A New Operating System, Built-In Recovery and Onboard Diagnostics**

A little update on where Brimstone Core is heading as we work towards our planned 1 December 2026 R1 release.

Over the past few months, Brimstone has grown considerably beyond the original idea of a simple replacement for ageing music-server hardware. We've now reached the point where it makes sense to rethink the operating system underneath it, rather than continually adapting a general-purpose Linux distribution.

**Moving from Debian to Buildroot**

Our current development systems are based on Debian Linux, which has served us well. However, Debian is designed to do thousands of different jobs, whereas Brimstone has one principal purpose: playing music reliably and at the best possible quality.

For R1, we're developing a dedicated operating system using Buildroot and the Linux 6.18 LTS kernel.

Buildroot isn't another Debian derivative. It allows us to assemble a Linux system specifically for Brimstone, including only the components we actually need.

The advantages are straightforward:

- Fewer unnecessary background services.
- Less software to maintain and fewer potential security vulnerabilities.
- A cleaner, more predictable operating environment.
- No conventional package-management updates interrupting normal use.
- Better control over hardware drivers and audio services.
- A stable operating-system foundation that doesn't need constantly changing.

We're not chasing the latest kernel or rewriting perfectly good software for the sake of it. If something works reliably, the intention is to keep it working.

The existing Brimstone music engine is being preserved. The new operating system is designed to run it, not replace it.

**Three Operating-System Slots — A, B and C**

One of the most significant changes is our new multi-slot boot and recovery architecture.

Rather than relying on a single operating-system installation, Brimstone will have three separate system environments.

**Slot A — Primary Operating System**

This is the normal working system, running Brimstone Core.

**Slot B — Secondary Operating System**

A separate operating-system image, used for updates and rollback.

When an update is installed, it can be written to the inactive slot while preserving the known-good installation.

If the updated system fails its startup checks, the machine can return to the previous working version.

**Slot C — Dedicated Recovery and Maintenance**

This is a separate recovery environment with its own operating system and tools.

It is designed to remain available even if both normal operating-system installations become unusable.

Slot C provides:

- Operating-system repair and restoration.
- Installation of verified OS updates.
- Boot-slot selection and rollback.
- Storage and filesystem diagnostics.
- Network diagnostics.
- System health reporting.
- Diagnostic log export.
- Recovery from USB media.

The recovery interface is deliberately text-menu based, so it does not depend on a working graphical desktop.

**Why does this matter?**

Because a music server should not become unusable simply because an update failed or a system file became damaged.

The intention is to provide recovery facilities built into the appliance itself, rather than requiring the owner to reinstall Linux from scratch.

**An Operating System That Cannot Easily Be Altered**

Another important change is that the normal operating-system images will be immutable.

In simple terms, the operating-system files are read-only during normal operation.

This helps protect against accidental system modifications, inappropriate software installations and other changes that can destabilise an otherwise working machine.

Music, playlists, metadata, databases and user settings remain separately stored and writable.

The system software is protected without making the customer's music collection read-only.

**Independent Brimstone Core Updates**

We're also separating operating-system updates from Brimstone application updates.

A correction to the music library, streaming services or playback interface should not require replacing the entire operating system.

Core will have its own signed application packages and a separate rollback mechanism.

The intention is for OS updates to be comparatively infrequent, with Core improvements delivered independently.

**Single-Disk and Multiple-Disk Installation**

Not everyone has a machine with several drives.

The new installer is being designed to support both single-disk and multi-disk computers.

Where multiple drives are available, the operating system and music storage can be separated.

The installer will also identify existing disks and provide clear choices before making changes. Existing music collections must not be inadvertently erased during installation.

**Audio Hardware**

Brimstone Core remains an audio-focused system.

Our planned output support includes HDMI multichannel PCM, external USB DACs, USB-to-SPDIF interfaces and compatible network audio endpoints.

This is particularly relevant to Meridian users, including those using the HD621 HDMI audio processor and digital loudspeaker systems.

Video playback and its associated audio remain functions of the iPad and Apple TV Control applications, rather than adding an unnecessary video playback system to Core itself.

**Where Are We Now?**

The new Buildroot appliance is already undergoing development and testing in an isolated virtual machine.

Initial tests have included successful booting, multi-slot recovery, failed-update rollback, USB recovery and operation of an unchanged Brimstone Core runtime in the new environment.

However, there is still work to complete, particularly with physical hardware, audio interfaces, installation and full system integration.

Our current Debian development installations are being retained while the new platform proves itself.

Nothing will replace the working system simply because the new one boots successfully in a virtual machine.

**The Aim for R1**

Ultimately, Brimstone should behave like a dedicated piece of hi-fi equipment.

Switch it on, select an album and enjoy the music.

The operating system, recovery facilities, diagnostics and updates should quietly take care of themselves without the owner needing to become a Linux administrator.

For those familiar with older Meridian and Sooloos equipment, that philosophy should sound familiar.

The technology underneath may be considerably more modern, but the objective remains the same: a reliable music system that concentrates on music rather than computer maintenance.

We're still targeting 1 December 2026 for R1, subject to completing the necessary testing.

More updates as development progresses.

**Chris**
**Brimstone Core**
https://core-audio.uk

Various music kit, lots of IT stuff