Hi all, As Ivan (@jonne) updated earlier this week on #spectrum, we've got initial cross-compilation support for aarch64 available in Spectrum development fork. It still needs some TLC before Spectrum PRs but is a great step forward. Our current ref. board is NXP i.MX8 but rootfs build should be fairly easy to modify for RPi4 configs already in nixpkgs for anyone who cares to try. Quick how-to for non-nixos host like Ubuntu: git clone -b aarch64-imx8-crosscompile https://github.com/tiiuae/nixpkgs-spectrum.git git clone -b aarch64-imx8-crosscompile https://github.com/tiiuae/spectrum.git cd spectrum/host/rootfs nix-build -I nixpkgs=../../../nixpkgs-spectrum Know issue: - crossSystem from https://github.com/tiiuae/spectrum/commit/aad5f90cf2ec931f2af5c8d5111a9fac11... is ignored on NixOS host but not on Ubuntu - maybe someone can point us why. Thanks, -Ville