diff --git a/hosts/modules/roles/build-machine.nix b/hosts/modules/roles/build-machine.nix
index d47ab232..8f5b67a6 100644
--- a/hosts/modules/roles/build-machine.nix
+++ b/hosts/modules/roles/build-machine.nix
@@ -35,7 +35,9 @@ in
       sane.services.nixserve.enable = true;
 
       # enable cross compilation
+      # TODO: do this via stdenv injection, linking into /run/binfmt the stuff in <nixpkgs:nixos/modules/system/boot/binfmt.nix>
       boot.binfmt.emulatedSystems = [ "aarch64-linux" ];
+      # corresponds to env var: NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1
       # nixpkgs.config.allowUnsupportedSystem = true;
 
       # granular compilation cache