Standardize Cross-Compilation and Enable Pure Flakes

docs/default.nix

@@ -1,6 +1,6 @@
 # Copyright (c) 2019-2024, see AUTHORS. Licensed under MIT License, see LICENSE.
 
-{ pkgs, home-manager, nmdSrc }:
+{ pkgs, crossPkgs ? pkgs, home-manager, nmdSrc }:
 
 let
   nmd = import nmdSrc { inherit pkgs; };
@@ -15,7 +15,7 @@ let
   };
 
   modules = import ../modules/module-list.nix {
-    inherit pkgs;
+    inherit pkgs crossPkgs;
     home-manager-path = home-manager.outPath;
     isFlake = true;
     targetSystem = "aarch64-linux/x86_64-linux";

flake.nix

@@ -5,9 +5,8 @@
     nixpkgs.url = "github:NixOS/nixpkgs";
 
     # for bootstrap zip ball creation and proot-termux builds, we use a fixed version of nixpkgs to ease maintanence.
-    # head of nixos-24.05 as of 2024-07-06
-    # note: when updating nixpkgs-for-bootstrap, update store paths of proot-termux in modules/environment/login/default.nix
-    nixpkgs-for-bootstrap.url = "github:NixOS/nixpkgs/49ee0e94463abada1de470c9c07bfc12b36dcf40";
+    # head of nixos-25.11 as of 2026-02-16
+    nixpkgs-for-bootstrap.url = "github:NixOS/nixpkgs/fa56d7d6de78f5a7f997b0ea2bc6efd5868ad9e8";
 
     home-manager = {
       url = "github:nix-community/home-manager";
@@ -78,6 +77,7 @@
         , config ? null
         , extraModules ? null
         , system ? null  # pkgs.stdenv.hostPlatform.system is used to detect user's arch
+        , bootstrapSystem ? pkgs.stdenv.hostPlatform.system
         }:
         if ! (builtins.elem pkgs.stdenv.hostPlatform.system [ "aarch64-linux" "x86_64-linux" ]) then
           throw
@@ -104,6 +104,7 @@
               inherit extraSpecialArgs home-manager-path pkgs;
               config.imports = modules;
               isFlake = true;
+              crossPkgs = import nixpkgs-for-bootstrap { crossSystem = pkgs.stdenv.hostPlatform.system; localSystem = bootstrapSystem; };
             });
 
       overlays.default = overlay;
@@ -118,9 +119,14 @@
               derivationAttrset;
           perArchCustomPkgs = arch: flattenArch arch
             (import ./pkgs {
-              _nativeSystem = system; # system to cross-compile from
-              system = "${arch}-linux"; # system to cross-compile to
-              nixpkgs = nixpkgs-for-bootstrap;
+              pkgs = import nixpkgs-for-bootstrap { inherit system; };
+              crossPkgs = import nixpkgs-for-bootstrap {
+                crossSystem = "${arch}-linux";
+                localSystem = system;
+              };
+              targetPkgs = import nixpkgs-for-bootstrap {
+                system = "${arch}-linux";
+              };
             }).customPkgs;
 
           docs = import ./docs {

modules/default.nix

@@ -6,6 +6,7 @@
 , pkgs ? import <nixpkgs> { }
 , home-manager-path ? <home-manager>
 , isFlake ? false
+, crossPkgs
 }:
 
 with pkgs.lib;
@@ -19,7 +20,7 @@ let
     else pkgs.config.nix-on-droid or (throw "No config file found! Create one in ~/.config/nixpkgs/nix-on-droid.nix");
 
   nodModules = import ./module-list.nix {
-    inherit pkgs home-manager-path isFlake targetSystem;
+    inherit pkgs home-manager-path isFlake targetSystem crossPkgs;
   };
 
   rawModule = evalModules {

modules/environment/login/default.nix

@@ -1,6 +1,6 @@
 # Copyright (c) 2019-2024, see AUTHORS. Licensed under MIT License, see LICENSE.
 
-{ config, lib, pkgs, initialPackageInfo, targetSystem, ... }:
+{ config, lib, pkgs, initialPackageInfo, targetSystem, crossPkgs, ... }:
 
 with lib;
 
@@ -12,6 +12,10 @@ let
   loginInner = pkgs.callPackage ./login-inner.nix {
     inherit config initialPackageInfo targetSystem;
   };
+
+  tallocStatic = crossPkgs.pkgsStatic.pkgsLLVM.callPackage ../../../pkgs/talloc { };
+
+  prootStatic = crossPkgs.pkgsStatic.pkgsLLVM.callPackage ../../../pkgs/proot-termux { talloc = tallocStatic; };
 in
 
 {
@@ -82,16 +86,7 @@ in
     };
 
     environment.files = {
-      inherit login loginInner;
-
-      prootStatic =
-        let
-          crossCompiledPaths = {
-            aarch64-linux = "/nix/store/7qd99m1w65x2vgqg453nd70y60sm3kay-proot-termux-static-aarch64-unknown-linux-android-unstable-2024-05-04";
-            x86_64-linux = "/nix/store/pakj3svvw84rhkzdc6211yhc2cgvc21f-proot-termux-static-x86_64-unknown-linux-android-unstable-2024-05-04";
-          };
-        in
-        "${crossCompiledPaths.${targetSystem}}";
+      inherit login loginInner prootStatic;
     };
 
   };

modules/environment/login/login-inner.nix

@@ -33,6 +33,9 @@ writeText "login-inner" ''
       # To prevent gc warnings of nix, see https://github.com/NixOS/nix/issues/3237
       export GC_NPROCS=1
 
+      echo "Setting up Nix store..."
+      ${nix}/bin/nix-store --init
+
       echo "Setting default user profile..."
       ${nix}/bin/nix-env --switch-profile /nix/var/nix/profiles/per-user/$USER/profile
 

modules/module-list.nix

@@ -4,6 +4,7 @@
 , home-manager-path
 , isFlake
 , targetSystem  # system to cross-compile to
+, crossPkgs
 }:
 
 [
@@ -31,7 +32,7 @@
   {
     _file = ./module-list.nix;
     _module.args = {
-      inherit home-manager-path isFlake targetSystem;
+      inherit home-manager-path isFlake targetSystem crossPkgs;
       pkgs = pkgs.lib.mkDefault pkgs;
     };
   }

pkgs/bootstrap.nix

@@ -1,13 +1,13 @@
 # Copyright (c) 2019-2024, see AUTHORS. Licensed under MIT License, see LICENSE.
 
-{ runCommand, nixDirectory, prootTermux, bash, pkgs, config, initialPackageInfo }:
+{ runCommand, closureInfo, prootTermux, bash, config, initialPackageInfo }:
 
 runCommand "bootstrap" { } ''
   mkdir --parents $out/{.l2s,bin,dev/shm,etc,root,tmp,usr/{bin,lib}}
   mkdir --parents $out/nix/var/nix/{profiles,gcroots}/per-user/nix-on-droid
 
-  cp --recursive ${nixDirectory}/store $out/nix/store
-  cp --recursive ${nixDirectory}/var $out/nix/var
+  mkdir --parents $out/nix/store
+  cp --recursive $(cat ${closureInfo}/store-paths) $out/nix/store
   chmod --recursive u+w $out/nix
 
   ln --symbolic ${initialPackageInfo.bash}/bin/sh $out/bin/sh

pkgs/default.nix

@@ -1,19 +1,24 @@
 # Copyright (c) 2019-2024, see AUTHORS. Licensed under MIT License, see LICENSE.
 
-{ nixpkgs
-, system  # system to compile for, user-facing name of targetSystem
-, _nativeSystem ? null  # system to cross-compile from, see flake.nix
+{ pkgs
+, crossPkgs
+, targetPkgs
 , nixOnDroidChannelURL ? null
 , nixpkgsChannelURL ? null
 , nixOnDroidFlakeURL ? null
 }:
 
 let
-  nativeSystem = if _nativeSystem == null then system else _nativeSystem;
-  nixDirectory = callPackage ./nix-directory.nix { inherit system; };
-  initialPackageInfo = import "${nixDirectory}/nix-support/package-info.nix";
+  targetSystem = crossPkgs.stdenv.hostPlatform.system;
 
-  pkgs = import nixpkgs { system = nativeSystem; };
+  # Use prebuilt bootstrap packages from nixpkgs cache
+  closureInfo = pkgs.closureInfo {
+    rootPaths = with targetPkgs; [ bash cacert nix ];
+  };
+  initialPackageInfo = {
+    inherit (targetPkgs) bash nix;
+    cacert = "${targetPkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
+  };
 
   urlOptionValue = url: envVar:
     let
@@ -24,8 +29,7 @@ let
       (if url == null then envValue else url);
 
   modules = import ../modules {
-    inherit pkgs;
-    targetSystem = system;
+    inherit pkgs crossPkgs targetSystem;
 
     isFlake = true;
 
@@ -56,16 +60,14 @@ let
   callPackage = pkgs.lib.callPackageWith (
     pkgs // customPkgs // {
       inherit (modules) config;
-      inherit callPackage nixpkgs nixDirectory initialPackageInfo;
-      targetSystem = system;
+      inherit callPackage closureInfo initialPackageInfo targetSystem;
     }
   );
 
   customPkgs = {
     bootstrap = callPackage ./bootstrap.nix { };
     bootstrapZip = callPackage ./bootstrap-zip.nix { };
-    prootTermux = callPackage ./cross-compiling/proot-termux.nix { };
-    tallocStatic = callPackage ./cross-compiling/talloc-static.nix { };
+    prootTermux = modules.config.environment.files.prootStatic;
   };
 in