Update to use custom base image

default.nix

@@ -1,4 +1,5 @@
 { pkgs ? import <nixos-unstable> { }
+, aarch64-image
 }:
 
 let
@@ -7,7 +8,7 @@ let
   };
 
   buildImage = pkgs.callPackage ./pkgs/build-image { };
-  aarch64Image = pkgs.callPackage ./pkgs/aarch64-image { };
+  aarch64Image = pkgs.callPackage ./pkgs/aarch64-image { aarch64-image = aarch64-image; };
   rockchip = uboot: pkgs.callPackage ./images/rockchip.nix {
     inherit uboot;
     inherit aarch64Image buildImage;

flake.lock

@@ -1,6 +1,40 @@
 {
   "nodes": {
+    "aarch64-linux-testing": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1673570754,
+        "narHash": "sha256-yI4UHNUKBUNQoHW6FvI4TsBElasr0bOufvJvaJ8lcrk=",
+        "ref": "refs/heads/main",
+        "rev": "11b7694a7e991862f980adbec8195969bf6d6e96",
+        "revCount": 2,
+        "type": "git",
+        "url": "https://git.asonix.dog/asonix/aarch64-linux-testing.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://git.asonix.dog/asonix/aarch64-linux-testing.git"
+      }
+    },
     "nixpkgs": {
+      "locked": {
+        "lastModified": 1673563280,
+        "narHash": "sha256-27+ZVRylsm7HwI3rUt6TFh3lrgzrvToJscL44fFd25Q=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "e0c17a48c475a03775833892373777892a6b8ff6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "master",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
       "locked": {
         "lastModified": 1673569462,
         "narHash": "sha256-iQUrbM/abkPzukU0GXwyb0ACBk1C9RH91Do0nL2/3jE=",
@@ -18,7 +52,8 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "aarch64-linux-testing": "aarch64-linux-testing",
+        "nixpkgs": "nixpkgs_2"
       }
     }
   },

flake.nix

@@ -1,11 +1,20 @@
 {
   description = "Build NixOS images for various ARM single computer boards";
   # pin this to unstable
-  inputs.nixpkgs.url = "github:nixos/nixpkgs/master";
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/master";
+    aarch64-linux-testing.url = "git+https://git.asonix.dog/asonix/aarch64-linux-testing.git";
+  };
 
-  outputs = { self, nixpkgs }: {
+  outputs = { self, nixpkgs, aarch64-linux-testing }: {
     packages.x86_64-linux = import ./. {
       pkgs = nixpkgs.legacyPackages.x86_64-linux;
+      aarch64-image =
+        let
+          base-path = aarch64-linux-testing.images.installer;
+          image-name = aarch64-linux-testing.nixosConfigurations.installer.config.sdImage.imageName;
+        in
+        "${base-path}/sd-image/${image-name}.zst";
     };
   };
 }

pkgs/aarch64-image/default.nix

@@ -1,15 +1,8 @@
-{ stdenv, fetchurl, zstd }:
+{ stdenv, fetchurl, zstd, aarch64-image }:
 
 stdenv.mkDerivation {
   name = "aarch64-image";
-  src = fetchurl {
-    # unfortunally there is no easy way right now to reproduce the same evaluation
-    # as hydra, since `pkgs.path` is embedded in the binary
-    # To get a new url use:
-    # $ curl -s -L -I -o /dev/null -w '%{url_effective}' "https://hydra.nixos.org/job/nixos/release-20.03/nixos.sd_image.aarch64-linux/latest/download/1"
-    url = "https://hydra.nixos.org/build/148774499/download/1/nixos-sd-image-21.05.1817.2262d7863a6-aarch64-linux.img.zst";
-    sha256 = "sha256-ILKsbYoqh76CwUte7PF1VmE53wiZBsaEl412OSQ2HV4=";
-  };
+  src = aarch64-image;
   preferLocalBuild = true;
   dontUnpack = true;
   dontBuild = true;
@@ -26,6 +19,6 @@ stdenv.mkDerivation {
   ];
 
   installPhase = ''
-    zstdcat $src > $out
+    zstdcat "$src" > $out
   '';
 }