Index: uspace/app/mkmfs/mkmfs.c
===================================================================
--- uspace/app/mkmfs/mkmfs.c	(revision b66ffb1f3508599ba6f10334b45548f19ad568c6)
+++ uspace/app/mkmfs/mkmfs.c	(revision 0395a7b2514b1bcda01647bc93cc98310c9ea4d8)
@@ -649,5 +649,5 @@
 		mark_bmap(ibmap_buf, i, FREE);
 
-	for (i = 2; i < sb->n_zones; ++i)
+	for (i = 2; i < sb->n_zones - sb->first_data_zone; ++i)
 		mark_bmap(zbmap_buf, i, FREE);