move all output modules to subdirectory, trash standard.nix

standard.nix isn't, is the essence here. Not all devices
support flashimage as it is currently defined - some
have diskimage, some have neither

modules/outputs/initramfs.nix

@@ -0,0 +1,58 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkEnableOption mkOption mkIf types;
+  inherit (pkgs) runCommand callPackage writeText;
+in
+{
+  options = {
+    boot.initramfs = {
+      enable = mkEnableOption "initramfs";
+    };
+    system.outputs = {
+      initramfs = mkOption {
+        type = types.package;
+        internal = true;
+        description = ''
+          Initramfs image capable of mounting the real root
+          filesystem
+        '';
+      };
+      systemConfiguration = mkOption {
+        type = types.package;
+        description = ''
+          pkgs.systemconfig for the configured filesystem,
+          contains 'activate' and 'init' commands
+        '';
+        internal = true;
+      };
+    };
+  };
+  config = mkIf config.boot.initramfs.enable {
+    kernel.config = {
+      BLK_DEV_INITRD = "y";
+      INITRAMFS_SOURCE = builtins.toJSON "${config.system.outputs.initramfs}";
+#      INITRAMFS_COMPRESSION_LZO = "y";
+    };
+
+    system.outputs = {
+      initramfs =
+        let inherit (pkgs.pkgsBuildBuild) gen_init_cpio;
+        in runCommand "initramfs.cpio" {} ''
+          cat << SPECIALS | ${gen_init_cpio}/bin/gen_init_cpio /dev/stdin > $out
+          dir /proc 0755 0 0
+          dir /dev 0755 0 0
+          nod /dev/console 0600 0 0 c 5 1
+          dir /target 0755 0 0
+          dir /target/persist 0755 0 0
+          dir /target/nix 0755 0 0
+          file /init ${pkgs.preinit}/bin/preinit 0755 0 0
+          SPECIALS
+        '';
+    };
+  };
+}