diff --git a/.gitignore b/.gitignore
index 0cc8925..a0393b1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 # nix build .#nixosConfigurations.exampleIso.config.system.build.isoImage
 result
+result-builds/
 .claude
 secrets/originals/
diff --git a/hosts/eris.nix b/hosts/eris.nix
index ca0ab2f..7a28024 100644
--- a/hosts/eris.nix
+++ b/hosts/eris.nix
@@ -1,9 +1,11 @@
-{...}: {
+{lib, ...}: {
   imports = [
     ./profiles/usb.nix
     ./profiles/common.nix
   ];
   config = {
     networking.hostName = "eris"; # U+2BF0 ⯰ ERIS FORM ONE
+    # Break mkDefault tie with installation-device.nix; installer needs root login.
+    services.openssh.settings.PermitRootLogin = lib.mkForce "yes";
   };
 }