diff --git a/firefox.spec b/firefox.spec
index 28a92ac..bd20257 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -272,6 +272,11 @@ make -f client.mk build
 %install
 rm -rf %{buildroot}
 
+# Make sure locale works for langpacks
+%{__cat} > %{_builddir}/obj/dist/bin/browser/defaults/preferences/firefox-l10n.js << EOF
+pref("general.useragent.locale", "chrome://global/locale/intl.properties");
+EOF
+
 make -C %{_builddir}/obj/browser/installer STRIP=/bin/true MOZ_PKG_FATAL_WARNINGS=0
 
 # Copy files to buildroot