Index: uspace/srv/fs/fat/fat_directory.c
===================================================================
--- uspace/srv/fs/fat/fat_directory.c	(revision cefd3ec7f24270a21f179ad8425fed1fb14956ba)
+++ uspace/srv/fs/fat/fat_directory.c	(revision 52ee8b7a687114d20880e01628f409cbfbc4fb3e)
@@ -87,6 +87,9 @@
 		if (!di->b) {
 			rc = fat_block_get(&di->b, di->bs, di->nodep, i, BLOCK_FLAGS_NONE);
-			if (rc != EOK)
+			if (rc != EOK) {
+				di->b = NULL:
 				return rc;
+			}
+			di->bnum = i;
 		}
 		aoff64_t o = di->pos % (BPS(di->bs) / sizeof(fat_dentry_t));