diff --git a/pkgs/by-name/ut/ut1999/package.nix b/pkgs/by-name/ut/ut1999/package.nix
index b70cbb0c3689..2dcf26039efc 100644
--- a/pkgs/by-name/ut/ut1999/package.nix
+++ b/pkgs/by-name/ut/ut1999/package.nix
@@ -23,7 +23,7 @@
 
 let
   version = "469e";
-  srcs = rec {
+  srcs = {
     x86_64-linux = fetchurl {
       url = "https://github.com/OldUnreal/UnrealTournamentPatches/releases/download/v${version}/OldUnreal-UTPatch${builtins.elemAt (lib.strings.splitString "-" version) 0}-Linux-amd64.tar.bz2";
       hash = "sha256-CMgGqjchsZcARaoVitkAUTKdmC6KmjZhFTkA6cy/aww=";
@@ -36,12 +36,10 @@ let
       url = "https://github.com/OldUnreal/UnrealTournamentPatches/releases/download/v${version}/OldUnreal-UTPatch${builtins.elemAt (lib.strings.splitString "-" version) 0}-Linux-x86.tar.bz2";
       hash = "sha256-y9bYAW77MOOYJ1elgsaIUygDch7B7HOPwor5s+FdPBQ=";
     };
-    x86_64-darwin = fetchurl {
+    aarch64-darwin = fetchurl {
       url = "https://github.com/OldUnreal/UnrealTournamentPatches/releases/download/v${version}/OldUnreal-UTPatch${builtins.elemAt (lib.strings.splitString "-" version) 0}-macOS.dmg";
       hash = "sha256-trOh9GLktwLfDuz5DWY+8fhHzDaq3KHsbdNSeNCR+g0=";
     };
-    # fat binary
-    aarch64-darwin = x86_64-darwin;
   };
   # This upload of the game is officially sanctioned by OldUnreal (who has received permission from Epic Games to link to archive.org) and the UT99.org community
   # This is a copy of the original Unreal Tournament: Game of the Year Edition (also known as UT or UT99). The first ISO contains the base game.
@@ -77,12 +75,11 @@ let
         cp -r System Sounds Textures maps $out
       '';
   systemDir =
-    rec {
+    {
       x86_64-linux = "System64";
       aarch64-linux = "SystemARM64";
       i686-linux = "System";
-      x86_64-darwin = "System";
-      aarch64-darwin = x86_64-darwin;
+      aarch64-darwin = "System";
     }
     .${stdenv.hostPlatform.system} or (throw "unsupported system: ${stdenv.hostPlatform.system}");
 in