diff -up a/build/autoconf/icu.orig.m4 b/build/autoconf/icu.m4
--- a/build/autoconf/icu.orig.m4	2016-12-09 09:11:01.227317790 +0100
+++ b/build/autoconf/icu.m4	2016-12-09 09:18:40.608712247 +0100
@@ -78,7 +78,7 @@
     # TODO: the l is actually endian-dependent
     # We could make this set as 'l' or 'b' for little or big, respectively,
     # but we'd need to check in a big-endian version of the file.
-    ICU_DATA_FILE="icudt${version}l.dat"
+    ICU_DATA_FILE="icudt${version}b.dat"
 
     MOZ_ICU_DATA_ARCHIVE=
 fi