diff --git a/common/cmd_scsi.c b/common/cmd_scsi.c
index cc08743..b17bebb 100644
--- a/common/cmd_scsi.c
+++ b/common/cmd_scsi.c
@@ -194,7 +194,7 @@
 
 block_dev_desc_t * scsi_get_dev(int dev)
 {
-	return((block_dev_desc_t *)&scsi_dev_desc[dev]);
+	return (dev < CFG_SCSI_MAX_DEVICE) ? &scsi_dev_desc[dev] : NULL;
 }