diff --git a/drivers/mtd/nand/raw/diskonchip.c b/drivers/mtd/nand/raw/diskonchip.c
index 8cbce39a33d9..79bea68e3c34 100644
--- a/drivers/mtd/nand/raw/diskonchip.c
+++ b/drivers/mtd/nand/raw/diskonchip.c
@@ -1221,7 +1221,7 @@ static inline int __init inftl_partscan(struct mtd_info *mtd, struct mtd_partiti
 		    (i == 0) && (ip->firstUnit > 0)) {
 			parts[0].name = " DiskOnChip IPL / Media Header partition";
 			parts[0].offset = 0;
-			parts[0].size = mtd->erasesize * ip->firstUnit;
+			parts[0].size = (uint64_t)mtd->erasesize * ip->firstUnit;
 			numparts = 1;
 		}