diff --git a/build_library/disk_util b/build_library/disk_util
index 5d220d755a..418c5e2857 100755
--- a/build_library/disk_util
+++ b/build_library/disk_util
@@ -432,7 +432,7 @@ def Format(options):
   WritePartitionTable(options, config, partitions)
 
   for part in partitions.itervalues():
-    if 'fs_type' not in part:
+    if part['type'] == 'blank' or 'fs_type' not in part:
       continue
 
     print "Formatting partition %s (%s) as %s" % (