diff --git a/hardware/raspberry_pi_4_model_B.nix b/hardware/raspberry_pi_4_model_B.nix
index 4e5a4c3..f71af4f 100644
--- a/hardware/raspberry_pi_4_model_B.nix
+++ b/hardware/raspberry_pi_4_model_B.nix
@@ -24,7 +24,7 @@
         enable = false; # NixOS wants to enable GRUB by default.
       };
     };
-    tmpOnTmpfs = true;
+    tmp.useTmpfs = true;
   };
 
   # File systems configuration for using the installer's partition layout