diff --git a/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommunicationLibUsb3Transfer.c b/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommunicationLibUsb3Transfer.c
index 773a7bd..dbff493 100644
--- a/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommunicationLibUsb3Transfer.c
+++ b/SourceLevelDebugPkg/Library/DebugCommunicationLibUsb3/DebugCommunicationLibUsb3Transfer.c
@@ -277,7 +277,7 @@
       //
       // The length of data which were transferred.
       //
-      CheckedUrb->Completed += (CheckedUrb->DataLen - EvtTrb->Length);
+      CheckedUrb->Completed += (((TRANSFER_TRB_NORMAL*)TRBPtr)->Length - EvtTrb->Length);
     } else {
       CheckedUrb->Result  |= EFI_USB_ERR_TIMEOUT;
     }