diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index e6d9467f6be0..37f174ccbcec 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -480,6 +480,10 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
 		/* let's register it anyway to preserve ordering */
 		slave->offset = 0;
 		slave->mtd.size = 0;
+
+		/* Initialize ->erasesize to make add_mtd_device() happy. */
+		slave->mtd.erasesize = parent->erasesize;
+
 		printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
 			part->name);
 		goto out_register;