diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index 03d5423..2ddc537 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Wed Jul 10 13:47:41 UTC 2019 - Bernhard Wiedemann <bwiedemann@suse.com>
+
+- Generate langpacks sequentially to avoid file corruption
+  from racy file writes (boo#1137970)
+
 -------------------------------------------------------------------
 Mon Jul  8 13:30:35 UTC 2019 - Wolfgang Rosenauer <wr@rosenauer.org>
 
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index a2af197..34e6817 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -449,7 +449,7 @@ install -m 644 %{SOURCE9} %{buildroot}%{progdir}/browser/defaults/preferences/fi
 mkdir -p %{buildroot}%{progdir}/browser/extensions
 truncate -s 0 %{_tmppath}/translations.{common,other}
 sed -r '/^(ja-JP-mac|en-US|)$/d;s/ .*$//' $RPM_BUILD_DIR/%{source_prefix}/browser/locales/shipped-locales \
-    | xargs -P 8 -n 1 -I {} /bin/sh -c '
+    | xargs -n 1 -I {} /bin/sh -c '
         locale=$1
         pushd $RPM_BUILD_DIR/compare-locales
         PYTHONPATH=lib \