diff --git a/default.nix b/default.nix
index 3449aaa..230eab1 100644
--- a/default.nix
+++ b/default.nix
@@ -51,9 +51,9 @@ let
     installPhase = ''
       mkdir -p $out/lib $out/include
       
-      # Copy library files
-      if [ -d lib ]; then
-        cp -r lib/* $out/lib/ || true
+      # Copy x64 library files (SDK has arch-specific subdirs)
+      if [ -d lib/x64 ]; then
+        cp -r lib/x64/* $out/lib/ || true
       fi
       
       # Copy header files