diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c
index 762ac53287d721b5fc303d95dc94532187b69992..e4ef8588a7470e46e2279f86b839cdda44e0e8dd 100644
--- a/drivers/mtd/nand/nand_util.c
+++ b/drivers/mtd/nand/nand_util.c
@@ -461,6 +461,9 @@ int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 
 #ifdef CONFIG_CMD_NAND_YAFFS
 	if (flags & WITH_YAFFS_OOB) {
+		if (flags & ~WITH_YAFFS_OOB)
+			return -EINVAL;
+
 		int pages;
 		pages = nand->erasesize / nand->writesize;
 		blocksize = (pages * nand->oobsize) + nand->erasesize;
diff --git a/include/nand.h b/include/nand.h
index b0a31b8f0205880f4464b2a8e99294a1662a8309..c5818f179da1f7401731213eda48d24f271b08ee 100644
--- a/include/nand.h
+++ b/include/nand.h
@@ -115,7 +115,9 @@ typedef struct nand_erase_options nand_erase_options_t;
 int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 		       u_char *buffer);
 
-#define WITH_YAFFS_OOB	(1 << 0) /* whether write with yaffs format */
+#define WITH_YAFFS_OOB	(1 << 0) /* whether write with yaffs format. This flag
+				  * is a 'mode' meaning it cannot be mixed with
+				  * other flags */
 
 int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
 			u_char *buffer, int flags);