uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/system/boot/systemd/shutdown.nix

@@ -0,0 +1,58 @@
+{ config, lib, utils, pkgs, ... }: let
+
+  cfg = config.systemd.shutdownRamfs;
+
+  ramfsContents = let
+    storePaths = map (p: "${p}\n") cfg.storePaths;
+    contents = lib.mapAttrsToList (_: v: "${v.source}\n${v.target}") (lib.filterAttrs (_: v: v.enable) cfg.contents);
+  in pkgs.writeText "shutdown-ramfs-contents" (lib.concatStringsSep "\n" (storePaths ++ contents));
+
+in {
+  options.systemd.shutdownRamfs = {
+    enable = lib.mkEnableOption "pivoting back to an initramfs for shutdown" // { default = true; };
+    contents = lib.mkOption {
+      description = "Set of files that have to be linked into the shutdown ramfs";
+      example = lib.literalExpression ''
+        {
+          "/lib/systemd/system-shutdown/zpool-sync-shutdown".source = writeShellScript "zpool" "exec ''${zfs}/bin/zpool sync"
+        }
+      '';
+      type = utils.systemdUtils.types.initrdContents;
+    };
+
+    storePaths = lib.mkOption {
+      description = ''
+        Store paths to copy into the shutdown ramfs as well.
+      '';
+      type = lib.types.listOf lib.types.singleLineStr;
+      default = [];
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.shutdownRamfs.contents."/shutdown".source = "${config.systemd.package}/lib/systemd/systemd-shutdown";
+    systemd.shutdownRamfs.storePaths = [pkgs.runtimeShell "${pkgs.coreutils}/bin"];
+
+    systemd.services.generate-shutdown-ramfs = {
+      description = "Generate shutdown ramfs";
+      wantedBy = [ "shutdown.target" ];
+      before = [ "shutdown.target" ];
+      unitConfig = {
+        DefaultDependencies = false;
+        ConditionFileIsExecutable = [
+          "!/run/initramfs/shutdown"
+        ];
+      };
+
+      path = [pkgs.util-linux pkgs.makeInitrdNGTool];
+      serviceConfig.Type = "oneshot";
+      script = ''
+        mkdir -p /run/initramfs
+        if ! mountpoint -q /run/initramfs; then
+          mount -t tmpfs tmpfs /run/initramfs
+        fi
+        make-initrd-ng ${ramfsContents} /run/initramfs
+      '';
+    };
+  };
+}