diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 84888447322907..ec1db1e19c0533 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2987,10 +2987,21 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 	sanitize_string(p->model, sizeof(p->model));
 	if (!mtd->name)
 		mtd->name = p->model;
+
 	mtd->writesize = le32_to_cpu(p->byte_per_page);
-	mtd->erasesize = le32_to_cpu(p->pages_per_block) * mtd->writesize;
+
+	/*
+	 * pages_per_block and blocks_per_lun may not be a power-of-2 size
+	 * (don't ask me who thought of this...). MTD assumes that these
+	 * dimensions will be power-of-2, so just truncate the remaining area.
+	 */
+	mtd->erasesize = 1 << (fls(le32_to_cpu(p->pages_per_block)) - 1);
+	mtd->erasesize *= mtd->writesize;
+
 	mtd->oobsize = le16_to_cpu(p->spare_bytes_per_page);
-	chip->chipsize = le32_to_cpu(p->blocks_per_lun);
+
+	/* See erasesize comment */
+	chip->chipsize = 1 << (fls(le32_to_cpu(p->blocks_per_lun)) - 1);
 	chip->chipsize *= (uint64_t)mtd->erasesize * p->lun_count;
 	chip->bits_per_cell = p->bits_per_cell;