diff --git a/pkgs/by-name/ko/koboldcpp/package.nix b/pkgs/by-name/ko/koboldcpp/package.nix
index 8f23b6167e3dd..a8266c55e85f9 100644
--- a/pkgs/by-name/ko/koboldcpp/package.nix
+++ b/pkgs/by-name/ko/koboldcpp/package.nix
@@ -129,8 +129,7 @@ effectiveStdenv.mkDerivation (finalAttrs: {
     (makeBool "LLAMA_CLBLAST" clblastSupport)
     (makeBool "LLAMA_VULKAN" vulkanSupport)
     (makeBool "LLAMA_METAL" metalSupport)
-    (lib.optionals cublasSupport "CUDA_DOCKER_ARCH=sm_${builtins.head cudaArches}")
-  ];
+  ] ++ lib.optionals cublasSupport [ "CUDA_DOCKER_ARCH=${builtins.head cudaArches}" ];
 
   installPhase = ''
     runHook preInstall