diff --git a/firefox.spec b/firefox.spec
index a2eb090..f1d3552 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -1,7 +1,7 @@
 # Set for local builds only
 %global disable_toolsets  0
 
-%global build_with_clang  1
+%global build_with_clang  0
 %ifarch i686
 # no debug package for the i686 because oom on i686 with debuginfos
 %global debug_package %{nil}
@@ -59,7 +59,7 @@
 %endif
 
 # we need python2 because of icu data gen
-%define use_bundled_python_2 1
+%define use_bundled_python_2 0
 
 %define bundle_gnome_extension 0
 
@@ -497,9 +497,7 @@ BuildRequires: openssl-devel
 %endif
 
 %if 0%{?big_endian}
-  %if 0%{?flatpak}
 BuildRequires:  icu
-  %endif
 %endif
 
 Obsoletes:      mozilla <= 37:1.7.13
@@ -1041,19 +1039,10 @@ esac
 ./mach python -c "import sys;print(sys.path)"
 
 %if 0%{?big_endian}
-  %if 0%{?flatpak}
-echo "Generate big endian version of config/external/icu/data/icud58l.dat"
-icupkg -tb config/external/icu/data/icudt67l.dat config/external/icu/data/icudt67b.dat
-ls -l config/external/icu/data
-rm -f config/external/icu/data/icudt*l.dat
-  %else
-echo "Generate big endian version of config/external/icu/data/icud64l.dat"
- ./mach python intl/icu_sources_data.py .
- rm -f config/external/icu/data/icudt*l.dat
-# mv config/external/icu/data/icudt64l.dat config/external/icu/data/icudt64b.dat
- ls -l config/external/icu/data
- cat /tmp/icu-make*
-  %endif
+  echo "Generate big endian version of config/external/icu/data/icud58l.dat"
+  icupkg -tb config/external/icu/data/icudt67l.dat config/external/icu/data/icudt67b.dat
+  ls -l config/external/icu/data
+  rm -f config/external/icu/data/icudt*l.dat
 %endif
 
 mkdir %{_buildrootdir}/bin || :
@@ -1168,6 +1157,7 @@ fi
 CPU_AVAILABLE=$(/usr/bin/getconf _NPROCESSORS_ONLN)
 # Pick the minimum from available CPUs or memory constrained number of jobs
 MOZ_SMP_FLAGS=-j$([ "$CPU_AVAILABLE" -le "$MEM_CONSTRAINED_JOBS" ] && echo "$CPU_AVAILABLE" || echo "$MEM_CONSTRAINED_JOBS")
+#MOZ_SMP_FLAGS=-j16
 
 %if 0%{?bundle_gtk3}
 # gtk3-private-setup-flags-env.inc