diff --git a/pkgs/os-specific/linux/kernel/manual-config.nix b/pkgs/os-specific/linux/kernel/manual-config.nix
index acf965d99507..377f7fc1c077 100644
--- a/pkgs/os-specific/linux/kernel/manual-config.nix
+++ b/pkgs/os-specific/linux/kernel/manual-config.nix
@@ -1,6 +1,5 @@
 { lib, buildPackages, runCommand, nettools, bc, bison, flex, perl, rsync, gmp, libmpc, mpfr, openssl
 , libelf, cpio, elfutils, zstd, python3Minimal, zlib, pahole
-, writeTextFile
 }:
 
 let
@@ -61,17 +60,12 @@ let
     ++ optional (lib.versionAtLeast version "5.13") zstd;
 
 
-  installkernel = writeTextFile { name = "installkernel"; executable=true; text = ''
-    #!${stdenv.shell} -e
+  installkernel = buildPackages.writeShellScript "installkernel" ''
+    set -e
     mkdir -p $4
     cp -av $2 $4
     cp -av $3 $4
-  ''; };
-
-  commonMakeFlags = [
-    "O=$(buildRoot)"
-  ] ++ lib.optionals (stdenv.hostPlatform.linux-kernel ? makeFlags)
-    stdenv.hostPlatform.linux-kernel.makeFlags;
+  '';
 
   drvAttrs = config_: kernelConf: kernelPatches: configfile:
     let
@@ -335,13 +329,15 @@ stdenv.mkDerivation ((drvAttrs config stdenv.hostPlatform.linux-kernel kernelPat
   hardeningDisable = [ "bindnow" "format" "fortify" "stackprotector" "pic" "pie" ];
 
   # Absolute paths for compilers avoid any PATH-clobbering issues.
-  makeFlags = commonMakeFlags ++ [
+  makeFlags = [
+    "O=$(buildRoot)"
     "CC=${stdenv.cc}/bin/${stdenv.cc.targetPrefix}cc"
     "HOSTCC=${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}cc"
     "ARCH=${stdenv.hostPlatform.linuxArch}"
   ] ++ lib.optional (stdenv.hostPlatform != stdenv.buildPlatform) [
     "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
-  ] ++ extraMakeFlags;
+  ] ++ (stdenv.hostPlatform.linux-kernel.makeFlags or [])
+    ++ extraMakeFlags;
 
   karch = stdenv.hostPlatform.linuxArch;
 } // (optionalAttrs (pos != null) { inherit pos; }))