diff --git a/pkgs/tools/archivers/rpm2targz/default.nix b/pkgs/tools/archivers/rpm2targz/default.nix
index ac5b132d7ab..1c4730c8de6 100644
--- a/pkgs/tools/archivers/rpm2targz/default.nix
+++ b/pkgs/tools/archivers/rpm2targz/default.nix
@@ -10,18 +10,7 @@
 , zstd
 }:
 
-let
-  shdeps = [
-    bzip2
-    coreutils
-    cpio
-    gnutar
-    gzip
-    xz
-    zstd
-  ];
-
-in stdenv.mkDerivation rec {
+stdenv.mkDerivation rec {
   pname = "rpm2targz";
   version = "2021.03.16";
 
@@ -31,9 +20,17 @@ in stdenv.mkDerivation rec {
     hash = "sha256-rcV+o9V2wWKznqSW2rA8xgnpQ02kpK4te6mYvLRC5vQ=";
   };
 
-  buildInputs = shdeps;
-
-  postPatch = ''
+  postPatch = let
+    shdeps = [
+      bzip2
+      coreutils
+      cpio
+      gnutar
+      gzip
+      xz
+      zstd
+    ];
+  in ''
     substituteInPlace rpm2targz --replace "=\"rpmoffset\"" "=\"$out/bin/rpmoffset\""
     # rpm2targz relies on the executable name
     # to guess what compressor it should use
@@ -41,9 +38,7 @@ in stdenv.mkDerivation rec {
     sed -i -e '2iexport PATH="${lib.makeBinPath shdeps}"' rpm2targz
   '';
 
-  preBuild = ''
-    makeFlagsArray+=(prefix=$out)
-  '';
+  installFlags = [ "prefix=$(out)" ];
 
   meta = with lib; {
     description = "Convert a .rpm file to a .tar.gz archive";
diff --git a/pkgs/tools/networking/zs-apc-spdu-ctl/default.nix b/pkgs/tools/networking/zs-apc-spdu-ctl/default.nix
index 275cc88e597..1a3d3ed7a35 100644
--- a/pkgs/tools/networking/zs-apc-spdu-ctl/default.nix
+++ b/pkgs/tools/networking/zs-apc-spdu-ctl/default.nix
@@ -20,11 +20,11 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [ cmake ];
-  buildInputs = [ fping libowlevelzs net-snmp ];
+  buildInputs = [ libowlevelzs net-snmp ];
 
   postPatch = ''
     substituteInPlace src/confent.cxx \
-      --replace /usr/sbin/fping "${lib.makeBinPath [fping]}/fping"
+      --replace /usr/sbin/fping "${fping}/bin/fping"
   '';
 
   meta = with lib; {
diff --git a/pkgs/tools/networking/zs-wait4host/default.nix b/pkgs/tools/networking/zs-wait4host/default.nix
index 4c8342256c7..b6b4c985dfe 100644
--- a/pkgs/tools/networking/zs-wait4host/default.nix
+++ b/pkgs/tools/networking/zs-wait4host/default.nix
@@ -1,4 +1,4 @@
-{ bash, coreutils, fetchurl, fping, lib, stdenvNoCC }:
+{ coreutils, fetchurl, fping, lib, stdenvNoCC }:
 
 stdenvNoCC.mkDerivation rec {
   pname = "zs-wait4host";
@@ -9,8 +9,6 @@ stdenvNoCC.mkDerivation rec {
     sha256 = "9F1264BDoGlRR7bWlRXhfyvxWio4ydShKmabUQEIz9I=";
   };
 
-  buildInputs = [ bash coreutils fping ];
-
   postPatch = ''
     for i in zs-wait4host zs-wait4host-inf; do
       substituteInPlace "$i" \
diff --git a/pkgs/tools/text/zstxtns-utils/default.nix b/pkgs/tools/text/zstxtns-utils/default.nix
index eebf0785394..362f2fca84d 100644
--- a/pkgs/tools/text/zstxtns-utils/default.nix
+++ b/pkgs/tools/text/zstxtns-utils/default.nix
@@ -1,5 +1,4 @@
-{ bash
-, coreutils
+{ coreutils
 , fetchurl
 , gnugrep
 , lib
@@ -18,7 +17,6 @@ stdenvNoCC.mkDerivation rec {
   };
 
   nativeBuildInputs = [ makeWrapper ];
-  buildInputs = [ bash coreutils gnugrep moreutils ];
 
   installPhase = ''
     runHook preInstall
@@ -27,8 +25,8 @@ stdenvNoCC.mkDerivation rec {
   '';
 
   postInstall = ''
-    wrapProgram $out/bin/zstxtns-merge --prefix PATH ":" "${lib.makeBinPath [coreutils gnugrep moreutils]}"
-    wrapProgram $out/bin/zstxtns-unmerge --prefix PATH ":" "${lib.makeBinPath [coreutils gnugrep]}"
+    wrapProgram $out/bin/zstxtns-merge --set PATH "${lib.makeBinPath [coreutils gnugrep moreutils]}"
+    wrapProgram $out/bin/zstxtns-unmerge --set PATH "${lib.makeBinPath [coreutils gnugrep]}"
   '';
 
   meta = with lib; {