Hi Ben, sorry for taking so long to respond. It seems, there has been an upstream change, that fixed the issue.

The error was this one:

Local evaluation for computing rebuilds
$ nix-env --extra-experimental-features no-url-literals --option system aarch64-darwin -f <nixpkgs> --nix-path nixpkgs=/Users/edean/.cache/nixpkgs-review/pr-459527-1/nixpkgs nixpkgs-overlays=/private/tmp/nix-shell-1673-462192242/tmpa3pj3v9z -qaP --xml --out-path --show-trace --no-allow-import-from-derivation
error:
       … while querying the derivation named 'flutter-wrapped-3.29.3-sdk-links'

       ……… 

       error: attribute 'macos-arm64' missing
       at /Users/edean/.cache/nixpkgs-review/pr-459527-1/nixpkgs/pkgs/development/compilers/flutter/engine/tools.nix:56:22:
           55|               url = "https://chrome-infra-packages.appspot.com/client?platform=${stdenv-constants.platform}&version=git_revision:${cipdCommit}";;
           56|               hash = cipdHashes.${stdenv-constants.platform};
             |                      ^
           57|             };
       Did you mean mac-arm64?
https://github.com/NixOS/nixpkgs/pull/459527 failed to build: Failed to list packages: nix-env failed with exit code 1

This Commit seems to have fixed the error. https://github.com/NixOS/nixpkgs/commit/78959ee6e3db1762024c4f8068cc9db57b8d5a6e#diff-a02d8cf7491f5e3faf1245b0bce2bad970c5924fd4b67e954d04cef7ee13147e

I still have no idea, why it wasn't broken for others, anyway...

python is possibly broken

       > python3.13(9980,0x1fba16240) malloc: *** error for object 0x103902de0: pointer being freed was not allocated
       > python3.13(9980,0x1fba16240) malloc: *** set a breakpoint in malloc_error_break to debug

https://github.com/NixOS/nixpkgs/issues/461396

So I use the nix.linux-builder for building aarch64-linux dependencies. But I am running into an issue on remote machines not trusting the generated paths since they are untrusted.

Even on my local machine, nix store verify --all is showing they are untrusted:

# nix store verify --all
...
path '/nix/store/0mapnivw6b3678v1b336j9dfxwjhmwc5-unit-dhcpcd.service' is untrusted
path '/nix/store/wy485gdjl7xwlaq5zz2aq55i3yjxry2b-dhcpcd.conf' is untrusted
path '/nix/store/36yijh6hzrg2r45sydbys92wrlwx5gs6-unit-systemd-fsck-.service' is untrusted
path '/nix/store/sr1pdx59gjbh949ai57lg6nzj19pgrpz-unit-script-network-setup-start' is untrusted
path '/nix/store/1j0930fgfwqgbxl517c08v64fmg0bnij-X-Restart-Triggers-systemd-timesyncd' is untrusted
path '/nix/store/421h6j088bq5q9qakabrsh004v2wgxp2-unit-network-setup.service' is untrusted
...

How do I configure the linux builder to sign the generated files so I can distribute the public key to both my local and remote machines?

this is what i observe with nixos-rebuild-ng

# nixos-rebuild-ng switch --flake .#rpi --ask-sudo-password --sudo --target-host "d@rpi"
[sudo] password for d@rpi:
building the system configuration...
warning: Git tree '/Users/d/.config/nix' is dirty
(d@rpi) Password:
(d@rpi) Password:
copying 6 paths...
copying path '/nix/store/3jrv1qr389dfin65n531zz4zb60pc8s1-nix.conf' to 'ssh://d@rpi'...
error: cannot add path '/nix/store/3jrv1qr389dfin65n531zz4zb60pc8s1-nix.conf' because it lacks a signature by a trusted key
error: unexpected end-of-file
Command 'nix-copy-closure --to d@rpi /nix/store/pjsmcl4633j54l4chsgqzv689kbkcrmi-nixos-system-rpi-25.11.20251005.d7f52a7' returned non-zero exit status 1.

Hey I've been using nix on mac for a while and really enjoy it!

I just got a new mac and trying to follow the guide on installing nix-darwin from https://github.com/nix-darwin/nix-darwin seems to fail.

1. I installed nix using the lix installer
2. I get an error when i try to install nix-darwin

Here is the output if i run the command in step 2 of the README.md:

$ sudo nix run nix-darwin/nix-darwin-25.05#darwin-rebuild -- switch
warning: $HOME ('/Users/tje') is not owned by you, falling back to the one defined in the 'passwd' file ('/var/root')
building the system configuration...
warning: Nix search path entry '/nix/var/nix/profiles/per-user/root/channels' does not exist, ignoring
error: file 'darwin' was not found in the Nix search path (add it using $NIX_PATH or -I)

This is a fresh macbook and i tried to follow the steps in the README.md so i'm not sure if I did something wrong or if the README is outdated.

niklaskorz: Thank you. Your message leads me to my mistake.
I did not create the /etc/nix-darwin folder but instead have my flake.nix in a different directory.

The fix was to run sudo nix run nix-darwin/master#darwin-rebuild -- switch --flake ~/darwin/#simple.

~/darwin/ is where I have my config.