add bcachefs iso

flake.nix

@@ -9,6 +9,7 @@
       mypkgs = pkgs:
         {
           iso = import lib/gen-iso.nix lib pkgs.system;
+          iso-bcachefs = import lib/gen-iso-bcachefs.nix lib pkgs.system;
         } //
         (lib.mapAttrs'
           (name: type: {

lib/gen-iso-bcachefs.nix

@@ -0,0 +1,20 @@
+lib:
+system:
+
+let
+  sys = lib.nixosSystem {
+    inherit system;
+    modules = [
+      ({ modulesPath, pkgs, ... }: {
+        imports = [
+          "${modulesPath}/installer/cd-dvd/installation-cd-minimal-new-kernel-no-zfs.nix"
+        ];
+        boot.kernelPackages = lib.mkForce pkgs.linuxPackages_testing_bcachefs;
+        boot.supportedFilesystems = [ "bcachefs" ];
+        isoImage.squashfsCompression = "gzip -Xcompression-level 1";
+      })
+    ];
+  };
+
+in
+sys.config.system.build.isoImage