NixOS Rockchip ARM Board Image Builder

This project creates NixOS disk images for Rockchip ARM-based boards with proper U-Boot integration, cross-compilation support, and multiple image variants (boot-only, demo, etc.). Currently supports the Radxa E52C (RK3582) and Radxa Rock 5A (RK3588S), with a modular design for easy addition of new boards.

File Structure

.
├── flake.nix                       # Nix flake with board + variant outputs
├── e52c-configuration.nix          # E52C board configuration
├── rock5a-configuration.nix        # Rock 5A board configuration
├── modules/
│   ├── rockchip-image.nix          # Rockchip support module
│   ├── assemble-monolithic-image.nix # Image assembly function
│   └── make-fat-fs.nix             # FAT32 filesystem builder
├── overlays/
│   └── uboot/                      # U-Boot patches and overlay
└── README.md                       # This file

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How It Works

1. Flake Structure (flake.nix)

• Provides board + variant build targets with automatic cross-compilation support
• Auto-detects build platform (x86_64 or aarch64) for optimal performance
• Supports explicit cross-compilation and native builds
• Modular design: each board can expose multiple variants (e.g. boot, demo)

2. Board Configurations

• Each board has its own config file (e52c-configuration.nix, rock5a-configuration.nix)
• Imports the rockchip-image.nix module
• Defines hardware-specific U-Boot, DTB, console, and image variants
• Board-specific tweaks (networking, packages, users) go here

3. Modules

• rockchip-image.nix → adds UKI boot, GPT partitioning, image variants
• assemble-monolithic-image.nix → glues together bootloader + partitions
• make-fat-fs.nix → helper to construct FAT32 boot partitions

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Supported Boards

Board	SoC	Variants	Status
Radxa E52C	RK3582	demo, boot	✅ Supported
Radxa Rock 5A	RK3588S	demo, boot	✅ Supported
Radxa E25	RK3568	TBD	🚧 Planned
Radxa Rock 5B	RK3588	TBD	🚧 Planned

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Building Images

Quick Start

# Build the default (demo) image for E52C:
nix build .#e52c

# Build an explicit variant:
nix build .#e52c-demo   # demo image with extra packages
nix build .#e52c-boot   # minimal boot-only image

# Build Rock 5A:
nix build .#rock5a
nix build .#rock5a-demo
nix build .#rock5a-boot

Available Build Targets

Target	Description
.#e52c	Alias → e52c-demo
.#e52c-demo	E52C with demo config (extra packages, dev tools)
.#e52c-boot	Minimal E52C boot-only image
.#rock5a	Alias → rock5a-demo
.#rock5a-demo	Rock 5A with demo config
.#rock5a-boot	Minimal Rock 5A boot-only image

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Cross-Compilation

Cross vs native is automatic:

• On x86_64 → images are cross-compiled for ARM (aarch64-linux)
• On ARM → images build natively

Example:

# Build E52C on x86_64 (cross)
nix build .#packages.x86_64-linux.e52c

# Build E52C on aarch64 host (native)
nix build .#packages.aarch64-linux.e52c

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Flashing Images

Same as before:

# eMMC full image
sudo dd if=result/nixos-rockchip-full.img of=/dev/mmcblk0 bs=1M status=progress sync

# SD card OS-only
sudo dd if=result/nixos-rockchip-os-only.img of=/dev/sdb bs=1M status=progress sync

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Adding New Boards

1. Create a config file (myboard-configuration.nix) that imports ./modules/rockchip-image.nix and sets rockchip.*.
2. Add your board to flake.nix in bootModules and/or demoModules.
3. Add build targets under packages:

myboard-demo = mkImg "myboard" self.demoModules.myboard;
myboard-boot = mkImg "myboard" self.bootModules.myboard;
myboard = mkImg "myboard" self.demoModules.myboard; # alias

4. Build:

nix build .#myboard
nix build .#myboard-demo
nix build .#myboard-boot

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Using as a flake Dependency

You can import this flake into another project’s flake.nix to reuse board builds:

{
  inputs = {
    nixos-on-arm.url = "github:projectinitiative/nixos-on-arm";
  };

  outputs = { self, nixpkgs, nixos-on-arm, ... }:
  let
    system = "x86_64-linux"; # or aarch64-linux
  in {
    packages.${system}.my-custom-build =
      nixos-on-arm.packages.${system}.e52c-demo;
  };
}

Then build with:

nix build .#my-custom-build

This way you can layer your own configuration on top while reusing the Rockchip base logic.

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Using as a config Dependency

Using in Another Configuration

You can also import the board base configs into your own NixOS configuration. The flake provides reusable module sets under demoModules. and bootModules..

Example: use the Rock5A demo setup inside your own config:

{ inputs, ... }:

{ imports = inputs.nixos-on-arm.demoModules.rock5a ++ [ ./my-networking.nix ./users.nix ]; }

Or, for a minimal boot-only base:

{ imports = inputs.nixos-on-arm.bootModules.e52c ++ [ ./my-services.nix ]; }

This way, you can treat the board setup as a foundation, while layering on your own modules and configs.

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Features

• 🚀 Cross-Platform: Build from x86_64 or native ARM
• 🎯 Variant System: Boot-only vs demo images per board
• 📦 UKI Boot: Unified kernel image booting
• 🛡️ GPT Layout: Proper GPT partitioning
• ⚡ Hardware Support: Rockchip-specific drivers & firmware
• 🔄 Reproducible: Fully declarative with Nix flakes

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