Hey, I got an ARM instance up and running last week using nixos-anywhere.
I since moved to x86 because some of the services I wanted to run exhibited poor performance on ARM but I’ve revived the initial config I used to build the ARM server and put it up on a branch Comparing main...hetzner-arm-old-config · alexghr/nix · GitHub (host b1droid). It’s a bit messy but it follows the examples from nixos-anywhere.
The install command I used is at the top of the configuration.nix file. Run this from your host and replace the ip of the target server.
nix run github:numtide/nixos-anywhere -- --flake .#b1droid root@<ip> --kexec "$(nix build --print-out-paths github:nix-community/nixos-images#packages.aarch64-linux.kexec-installer-nixos-2211-noninteractive)/nixos-kexec-installer-noninteractive-aarch64-linux.tar.gz"
I used the 22.11 image because 23.05 wasn’t available in nixos-images at the time.
Hope this helps 