diff --git a/pkgs/by-name/ro/roboto/package.nix b/pkgs/by-name/ro/roboto/package.nix
index b2b7880f9726..fe4a666fbc6a 100644
--- a/pkgs/by-name/ro/roboto/package.nix
+++ b/pkgs/by-name/ro/roboto/package.nix
@@ -30,7 +30,7 @@ stdenvNoCC.mkDerivation rec {
       ttx -v -o $fontname.xml $file
       substituteInPlace $fontname.xml \
         --replace-fail "<usWidthClass value=\"5\"/>" "<usWidthClass value=\"3\"/>"
-      ttx $fontname.xml -o $fontname.ttf
+      ttx --no-recalc-timestamp $fontname.xml -o $fontname.ttf
     done
 
     install -Dm644 *.ttf -t $out/share/fonts/truetype