diff --git a/extensions/compat_xtables.h b/extensions/compat_xtables.h
index 78a7fbf..d8882ac 100644
--- a/extensions/compat_xtables.h
+++ b/extensions/compat_xtables.h
@@ -35,7 +35,7 @@
 		ntohs((addr).s6_addr16[5]), \
 		ntohs((addr).s6_addr16[6]), \
 		ntohs((addr).s6_addr16[7])
-#	define NIP6_FMT "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x"
+#	define NIP6_FMT "%04hx:%04hx:%04hx:%04hx:%04hx:%04hx:%04hx:%04hx"
 #endif
 #if !defined(NIPQUAD) && !defined(NIPQUAD_FMT)
 #	define NIPQUAD(addr) \
@@ -43,7 +43,7 @@
 		((const unsigned char *)&addr)[1], \
 		((const unsigned char *)&addr)[2], \
 		((const unsigned char *)&addr)[3]
-#	define NIPQUAD_FMT "%u.%u.%u.%u"
+#	define NIPQUAD_FMT "%hhu.%hhu.%hhu.%hhu"
 #endif
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 9, 0)