diff --git a/dlls/ntdll/cdrom.c b/dlls/ntdll/cdrom.c
index 574f737..465140e 100644
--- a/dlls/ntdll/cdrom.c
+++ b/dlls/ntdll/cdrom.c
@@ -1725,7 +1725,10 @@ static NTSTATUS CDROM_ScsiGetCaps(PIO_SCSI_CAPABILITIES caps)
  */
 static NTSTATUS CDROM_GetAddress(int fd, SCSI_ADDRESS* address)
 {
-    UCHAR portnum, busid, targetid, lun;
+    UCHAR portnum = 0;
+    UCHAR busid = 0;
+    UCHAR targetid = 0;
+    UCHAR lun = 0;
 
     address->Length = sizeof(SCSI_ADDRESS);
     if ( ! CDROM_GetInterfaceInfo(fd, &portnum, &busid, &targetid, &lun))
@@ -1734,7 +1737,7 @@ static NTSTATUS CDROM_GetAddress(int fd, SCSI_ADDRESS* address)
     address->PortNumber = portnum; /* primary=0 secondary=1 for ide */
     address->PathId = busid;       /* always 0 for ide */
     address->TargetId = targetid;  /* master=0 slave=1 for ide */
-    address->Lun = lun;
+    address->Lun = lun;            /* default is 0 for SCSI */
     return STATUS_SUCCESS;
 }