Alpine Linux on arm install Part 2

Step 2: Get U-Boot

Overview

Build u-boot for the Orange Pi Zero using Nix's cross-compilation infrastructure.

Build u-boot with Nix

nix-build '<nixpkgs>' -A pkgsCross.aarch64-multiplatform.ubootOrangePiZero2

The resulting u-boot-sunxi-with-spl.bin will be in ./result/.

Notes from the NixOS U-Boot Wiki

Reference: https://wiki.nixos.org/wiki/U-Boot

Cross-compilation package sets

Nix provides cross-compilation package sets for ARM targets:

Target Architecture	Package Set
AArch64	`aarch64-multiplatform`
ARMv7l	`armv7l-hf-multiplatform`
ARMv6l	`raspberryPi`

General command format

nix-build -A [pkgsCross.$cross_name.]$packageName

When building from an x86_64 host for an ARM board, use the pkgsCross prefix. On a native AArch64 system, the prefix can be omitted:

nix-build -A ubootOrangePiZero2

Finding available u-boot packages

To find board-specific u-boot packages in nixpkgs, search for uboot in the package set:

nix-env -qaP -A nixpkgs.pkgsCross.aarch64-multiplatform | grep -i uboot

For board defconfigs and SD card write offsets, consult the official U-Boot documentation or board-specific pages, as the large variety of ecosystems makes a single guide impractical.