diff --git a/pkgs/applications/blockchains/monero-gui/default.nix b/pkgs/applications/blockchains/monero-gui/default.nix
index 43a35b1328b..c079fa88a70 100644
--- a/pkgs/applications/blockchains/monero-gui/default.nix
+++ b/pkgs/applications/blockchains/monero-gui/default.nix
@@ -75,10 +75,11 @@ stdenv.mkDerivation rec {
                 'add_subdirectory(monero EXCLUDE_FROM_ALL)'
   '';
 
-  cmakeFlags = [
-    "-DCMAKE_INSTALL_PREFIX=$out/bin"
-    "-DARCH=${arch}"
-  ];
+  preConfigure = ''
+    # because $out needs to be expanded
+    cmakeFlagsArray+=("-DCMAKE_INSTALL_PREFIX=$out/bin")
+    cmakeFlagsArray+=("-DARCH=${arch}")
+  '';
 
   desktopItem = makeDesktopItem {
     name = "monero-wallet-gui";