diff --git a/pkgs/applications/networking/browsers/firefox-bin/default.nix b/pkgs/applications/networking/browsers/firefox-bin/default.nix
index 9f4923a7ec5f..a1442cfb3ebb 100644
--- a/pkgs/applications/networking/browsers/firefox-bin/default.nix
+++ b/pkgs/applications/networking/browsers/firefox-bin/default.nix
@@ -201,7 +201,6 @@ stdenv.mkDerivation {
       url = "http://www.mozilla.org/en-US/foundation/trademarks/policy/";
     };
     platforms = builtins.attrNames mozillaPlatforms;
-    timeout = 86400; # 24 hours (increased from the Hydra default of 10h, c.f. #129115)
     maintainers = with maintainers; [ taku0 lovesegfault ];
   };
 }
diff --git a/pkgs/applications/networking/browsers/firefox/packages.nix b/pkgs/applications/networking/browsers/firefox/packages.nix
index 3aa0eeece9b8..109c757c15f1 100644
--- a/pkgs/applications/networking/browsers/firefox/packages.nix
+++ b/pkgs/applications/networking/browsers/firefox/packages.nix
@@ -21,6 +21,7 @@ rec {
       badPlatforms = lib.platforms.darwin;
       broken = stdenv.buildPlatform.is32bit; # since Firefox 60, build on 32-bit platforms fails with "out of memory".
                                              # not in `badPlatforms` because cross-compilation on 64-bit machine might work.
+      maxSilent = 14400; # 4h, double the default of 7200s (c.f. #129212, #129115)
       license = lib.licenses.mpl20;
     };
     tests = [ nixosTests.firefox ];