diff --git a/drivers/dfu/dfu_mtd.c b/drivers/dfu/dfu_mtd.c
index 894b570..a31d480 100644
--- a/drivers/dfu/dfu_mtd.c
+++ b/drivers/dfu/dfu_mtd.c
@@ -268,9 +268,9 @@
 	st = strsep(&s, " ");
 	if (!strcmp(st, "raw")) {
 		dfu->layout = DFU_RAW_ADDR;
-		dfu->data.mtd.start = simple_strtoul(s, &s, 16);
+		dfu->data.mtd.start = hextoul(s, &s);
 		s++;
-		dfu->data.mtd.size = simple_strtoul(s, &s, 16);
+		dfu->data.mtd.size = hextoul(s, &s);
 	} else if ((!strcmp(st, "part")) || (!strcmp(st, "partubi"))) {
 		char mtd_id[32];
 		struct mtd_device *mtd_dev;