diff --git a/nixos/modules/system/boot/stage-1.nix b/nixos/modules/system/boot/stage-1.nix
index 84520438e06e..7fbb7521d0f3 100644
--- a/nixos/modules/system/boot/stage-1.nix
+++ b/nixos/modules/system/boot/stage-1.nix
@@ -571,7 +571,7 @@ in
       { assertion = !config.boot.loader.supportsInitrdSecrets ->
           all (source:
             builtins.isPath source ||
-            (builtins.isString source && hasPrefix source builtins.storeDir))
+            (builtins.isString source && hasPrefix builtins.storeDir source))
           (attrValues config.boot.initrd.secrets);
         message = ''
           boot.loader.initrd.secrets values must be unquoted paths when