diff --git a/modules/home-manager/programs/copilot-fix.nix b/modules/home-manager/programs/copilot-fix.nix
index a28c37b..18e105e 100644
--- a/modules/home-manager/programs/copilot-fix.nix
+++ b/modules/home-manager/programs/copilot-fix.nix
@@ -1,11 +1,20 @@
-{ pkgs, ... }:
+{ pkgs }:
 
 pkgs.github-copilot-cli.overrideAttrs (old: {
   postFixup = (old.postFixup or "") + ''
     if [ -f "$out/bin/.copilot-wrapped" ]; then
-      echo "Patching copilot wrapper to remove --no-warnings..."
-      substituteInPlace "$out/bin/.copilot-wrapped" \
-        --replace "--no-warnings" ""
+      echo "Patching copilot wrapper (binary-safe)..."
+
+      tmpfile=$(mktemp)
+
+      # remove the offending flag safely
+      cat "$out/bin/.copilot-wrapped" \
+        | tr -d '\000' \
+        | sed 's/--no-warnings//g' \
+        > "$tmpfile"
+
+      chmod +x "$tmpfile"
+      mv "$tmpfile" "$out/bin/.copilot-wrapped"
     fi
   '';
 })