# Talos CM5 Builder

Custom Talos Linux images for Raspberry Pi 5 / CM5 on Compute Blade hardware.

<a href="https://hub.docker.com/r/svrnty/talos-rpi5" target="_blank"><img src="https://img.shields.io/docker/v/svrnty/talos-rpi5?sort=semver&label=talos-rpi5&logo=docker&arch=arm64" alt="Docker Hub"></a>
<a href="https://hub.docker.com/r/svrnty/talos-rpi5" target="_blank"><img src="https://img.shields.io/docker/pulls/svrnty/talos-rpi5?logo=docker" alt="Docker Pulls"></a>
<a href="https://hub.docker.com/r/svrnty/talos-rpi5" target="_blank"><img src="https://img.shields.io/docker/image-size/svrnty/talos-rpi5?sort=semver&logo=docker&arch=arm64" alt="Docker Image Size"></a>

The official Talos Image Factory does not support CM5 — the mainline kernel lacks CM5 device trees and RP1 driver support. This builder uses the RPi downstream kernel (via [talos-rpi5/talos-builder](https://github.com/talos-rpi5/talos-builder) patches) to produce working CM5 images with our extensions and overclock config.

## Current versions

| Component | Version |
|-----------|---------|
| Talos Linux | <a href="https://github.com/siderolabs/talos" target="_blank"><img src="https://img.shields.io/badge/talos-v1.12.3-blue?logo=kubernetes&logoColor=white" alt="Talos version"></a> |
| RPi Kernel | <a href="https://github.com/raspberrypi/linux" target="_blank"><img src="https://img.shields.io/badge/kernel-6.12.47-blue?logo=linux&logoColor=white" alt="Kernel version"></a> |
| iscsi-tools | <a href="https://github.com/siderolabs/extensions" target="_blank"><img src="https://img.shields.io/badge/iscsi--tools-v0.1.6-blue?logo=docker" alt="iscsi-tools version"></a> |
| util-linux-tools | <a href="https://github.com/siderolabs/extensions" target="_blank"><img src="https://img.shields.io/badge/util--linux--tools-2.40.4-blue?logo=docker" alt="util-linux-tools version"></a> |

## Image tags

Release images are published to <a href="https://hub.docker.com/r/svrnty/talos-rpi5" target="_blank"><code>docker.io/svrnty/talos-rpi5</code></a> with the format:

```
v<talos>-k<kernel>-<revision>
```

For example: `v1.12.3-k6.12.47-2`

| Segment | Meaning |
|---------|---------|
| `v1.12.3` | Upstream Talos Linux version |
| `k6.12.47` | RPi downstream kernel version |
| `2` | Build revision (bumped for config/patch changes on the same upstream versions) |

## Usage

### Install from raw disk image

Download `metal-arm64.raw.zst` from the [latest release](../../releases/latest) and flash to eMMC:

```bash
zstd -d metal-arm64.raw.zst -o metal-arm64.raw
# Flash to eMMC/SD via your preferred tool (dd, balenaEtcher, etc.)
```

### Upgrade an existing node

```bash
talosctl upgrade --image docker.io/svrnty/talos-rpi5:v1.12.3-k6.12.47-2
```

> **Note:** In-place upgrades use GRUB with `--no-nvram` to work around the RPi5/CM5 `SetVariableRT` firmware limitation. This patch is included but not yet tested in production — re-flashing the disk image is the proven fallback.

```bash
# Fallback: re-flash method
zstd -d metal-arm64.raw.zst -o metal-arm64.raw
# Flash to eMMC/SD via your preferred tool
```

### What's included

- RPi downstream kernel with CM5/RP1 support (4K page size, aligned with upstream Talos)
- GRUB bootloader with `--no-nvram` for reliable `talosctl upgrade` on RPi5/CM5
- Overclock: 2.6GHz (`arm_freq=2600`, `over_voltage_delta=50000`, `arm_boost=1`)
- Extensions: `iscsi-tools`, `util-linux-tools`

## Known issues

### ~~No serial console output after boot~~ (Fixed)

The overlay was using `console=ttyAMA0` (GPIO 14/15 UART) but the RPi5/CM5 debug UART is `ttyAMA10`. Fixed by switching to `console=ttyAMA10,115200` and adding `earlycon=pl011,0x107d001000,115200n8` for early boot output. Also added `[pi5] enable_uart=0` to `config.txt` to match upstream and avoid U-Boot compatibility issues.

*Upstream: <a href="https://github.com/talos-rpi5/talos-builder/issues/4" target="_blank">talos-builder#4</a>*

### Install disk config ignored on SBCs

Talos ignores the `machine.install.disk` config field on SBC platforms. You **must flash the disk image directly** to your target disk (eMMC, SD, NVMe). Booting from USB or NVMe also requires flashing directly to that disk — the image targets SD (`mmcblk0`) by default.

*Upstream: <a href="https://github.com/talos-rpi5/talos-builder/issues/22" target="_blank">talos-builder#22</a>*

## Roadmap

This project targets production-ready Talos clusters on RPi5/CM5 hardware.

| Status | Milestone | Description |
|--------|-----------|-------------|
| Untested | **4K page size** | Aligned with upstream Talos kernel config. Reduces memory overhead and improves workload compatibility (Longhorn, jemalloc, F2FS, etc.). |
| Untested | **Reliable in-place upgrades** | Force GRUB bootloader with `--no-nvram` on arm64 to work around the `SetVariableRT` firmware limitation (<a href="https://github.com/talos-rpi5/talos-builder/issues/21" target="_blank">talos-builder#21</a>). |
| Untested | **Serial console fix** | Use correct debug UART (`ttyAMA10`) with `earlycon` for early boot output. |
| Pending | **NVMe boot support** | Produce images that target NVMe directly, or document a supported NVMe boot flow. |

## Building

For local builds, CI/CD setup, runner configuration, and project structure, see [TECHNICAL.md](TECHNICAL.md).

## License

This project is licensed under the [Mozilla Public License 2.0](LICENSE).

It builds upon the following MPL 2.0 licensed upstream projects:

- [siderolabs/talos](https://github.com/siderolabs/talos) — Talos Linux OS
- [siderolabs/pkgs](https://github.com/siderolabs/pkgs) — Talos package definitions
- [talos-rpi5/sbc-raspberrypi5](https://github.com/talos-rpi5/sbc-raspberrypi5) — Raspberry Pi 5 SBC overlay

Our patches to these projects are in the `patches/` directory and are distributed under the same MPL 2.0 terms.