Index: uspace/app/mkexfat/mkexfat.c
===================================================================
--- uspace/app/mkexfat/mkexfat.c	(revision aa37d6fc3681167b2e699b27ebb00de96a9368b4)
+++ uspace/app/mkexfat/mkexfat.c	(revision 09c954ba81b1fc857478c0408ed2e59077744202)
@@ -252,8 +252,9 @@
 
 	mbs->data_clusters = host2uint32_t_le(cfg->total_clusters - 
-	    div_round_up(cfg->data_start_sector, cfg->cluster_size));
+	    div_round_up(cfg->data_start_sector * cfg->sector_size,
+	    cfg->cluster_size));
 
 	mbs->rootdir_cluster = host2uint32_t_le(cfg->rootdir_cluster);
-	mbs->volume_serial = 0;
+	mbs->volume_serial = host2uint32_t_le(0xe1028172);
 	mbs->version.major = 1;
 	mbs->version.minor = 0;
@@ -597,6 +598,6 @@
 	/* Initialize the volume label dentry */
 	d->type = EXFAT_TYPE_VOLLABEL;
-	str_to_utf16(d->vollabel.label, 7, "HELENOS");
-	d->vollabel.size = 7;
+	str_to_utf16(d->vollabel.label, 8, "HELENOS ");
+	d->vollabel.size = 8;
 
 	d++;