diff --git a/rpi/default.nix b/rpi/default.nix
index 1ee75e9..2cd320a 100644
--- a/rpi/default.nix
+++ b/rpi/default.nix
@@ -18,7 +18,12 @@
 
     loader = {
       grub.enable = lib.mkDefault false;
-      generic-extlinux-compatible.enable = lib.mkDefault true;
+      generic-extlinux-compatible = {
+        enable = lib.mkDefault true;
+        # We want to use the device tree provided by firmware, so don't
+        # add FDTDIR to the extlinux conf file.
+        useGenerationDeviceTree = false;
+      };
     };
   };
   hardware.enableRedistributableFirmware = true;