Try #1579:

Author: iohk-bors[bot]

.buildkite/pipeline.yml

@@ -41,7 +41,7 @@ steps:
 
   - label: 'Check that the haskell.nix roots do not require IFDs'
     command:
-      - nix build .#roots.x86_64-linux --option allow-import-from-derivation false
+      - yes | nix build .#roots.x86_64-linux --option allow-import-from-derivation false
     agents:
       system: x86_64-linux
 

flake.nix

@@ -147,4 +147,14 @@
           ];
         };
     });
+
+  # --- Flake Local Nix Configuration ----------------------------
+  nixConfig = {
+    # This sets the flake to use the IOG nix cache.
+    # Nix should ask for permission before using it,
+    # but remove it here if you do not want it to.
+    extra-substituters = ["https://cache.iog.io"];
+    extra-trusted-public-keys = ["hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ="];
+    allow-import-from-derivation = "true";
+  };
 }