diff --git a/pkgs/misc/arm-trusted-firmware/default.nix b/pkgs/misc/arm-trusted-firmware/default.nix
index 743e429c0051..b76b601046ba 100644
--- a/pkgs/misc/arm-trusted-firmware/default.nix
+++ b/pkgs/misc/arm-trusted-firmware/default.nix
@@ -18,7 +18,7 @@
 }:
 
 let
-  buildArmTrustedFirmware =
+  buildArmTrustedFirmware = lib.makeOverridable (
     {
       filesToInstall,
       installDir ? "$out",
@@ -109,7 +109,8 @@ let
           // extraMeta;
       }
       // builtins.removeAttrs args [ "extraMeta" ]
-    );
+    )
+  );
 
 in
 {