diff --git a/Sources/Fault/Entries/atpg.swift b/Sources/Fault/Entries/atpg.swift
index 51bc6e2..31f7782 100644
--- a/Sources/Fault/Entries/atpg.swift
+++ b/Sources/Fault/Entries/atpg.swift
@@ -155,8 +155,12 @@ extension Fault {
                 print("Read \(etvSetVectors.count) externally-generated vectors to verify.")
             }
 
-            if let tvGenerator = etvGen, ETVGFactory.validNames.contains(tvGenerator) {
-                let etvgen = ETVGFactory.get(name: tvGenerator)!
+            if let tvGenerator = etvGen {
+                guard let etvgen = ETVGFactory.get(name: tvGenerator) else {
+                    Stderr.print("Unknown external test vector generator '\(tvGenerator)'.")
+                    Foundation.exit(EX_USAGE)
+                }
+                
                 let benchUnwrapped = bench! // Program exits if etvGen.value isn't nil and bench.value is or vice versa
 
                 if !fileManager.fileExists(atPath: benchUnwrapped) {
diff --git a/default.nix b/default.nix
index 1f0997a..c3d21f2 100644
--- a/default.nix
+++ b/default.nix
@@ -58,12 +58,6 @@ stdenv.mkDerivation (finalAttrs: {
   ];
   
   configurePhase = generated.configure;
-
-  installPhase = ''
-    binPath="$(swiftpmBinPath)"
-    mkdir -p $out/bin
-    cp $binPath/fault $out/bin/fault
-  '';
   
   # This doesn't work on Linux otherwise and I don't know why.
   preBuild = if stdenv.isDarwin then "" else ''
@@ -81,17 +75,31 @@ stdenv.mkDerivation (finalAttrs: {
   '';
   
   checkPhase = ''
+    runHook preCheck
     ${finalAttrs.faultEnv}
     PYTEST_FAULT_BIN="$(swiftpmBinPath)/fault" pytest
+    runHook postCheck
+  '';
+
+  installPhase = ''
+    runHook preInstall
+    binPath="$(swiftpmBinPath)"
+    mkdir -p $out/bin
+    cp $binPath/fault $out/bin/fault
+    ln -s ${nl2bench}/bin/nl2bench $out/bin/nl2bench
+    runHook postInstall
   '';
   
   fixupPhase = ''
+    runHook preFixup
     wrapProgram $out/bin/fault\
       --prefix PYTHONPATH : ${pyenv}/${pyenv.sitePackages}\
       --prefix PATH : ${verilog}/bin\
+      --prefix PATH : ${quaigh}/bin\
       --prefix PATH : ${yosys}/bin\
       --set PYTHON_LIBRARY ${pyenv}/lib/lib${pyenv.libPrefix}${swiftPackages.stdenv.hostPlatform.extensions.sharedLibrary}\
       --set FAULT_IVL_BASE ${verilog}/lib/ivl
+    runHook postFixup
   '';
   
   meta = with lib; {
diff --git a/docs/Source/installation.md b/docs/Source/installation.md
index 532aab0..1c3fba1 100644
--- a/docs/Source/installation.md
+++ b/docs/Source/installation.md
@@ -14,8 +14,8 @@ and system configuration.
 To install Nix, follow OpenLane 2's Nix installation guide at
 https://openlane2.readthedocs.io/en/stable/getting_started/common/nix_installation/index.html.
 
-Afterwards, running Fault is simply `nix run github:AUCOHL/Fault`. To make
-the `fault` command available in path, you can
+Afterwards, to make the `fault` command (and the requisite `nl2bench` tool for
+using alternative ATPGs) available in PATH, you can simply invoke
 `nix profile install github:AUCOHL/Fault`.
 
 ## Docker