diff --git a/Asec.h b/Asec.h
index 136ad3b..dd64fd0 100644
--- a/Asec.h
+++ b/Asec.h
@@ -33,6 +33,7 @@
     unsigned char c_chain;
 
 #define ASEC_SB_C_OPTS_NONE 0
+#define ASEC_SB_C_OPTS_EXT4 1
     unsigned char c_opts;
 
 #define ASEC_SB_C_MODE_NONE 0