From edd477101c23fd6f2ee28b07b2462114b7efab6c Mon Sep 17 00:00:00 2001
From: Hubert Denkmair <hubert@denkmair.de>
Date: Sun, 1 May 2016 17:55:46 +0200
Subject: [PATCH] return WCID GUID only for gs_usb interface, not for the dfu
 one

---
 src/usbd_gs_can.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/usbd_gs_can.c b/src/usbd_gs_can.c
index 8c98816..52f7bae 100644
--- a/src/usbd_gs_can.c
+++ b/src/usbd_gs_can.c
@@ -492,10 +492,13 @@ bool USBD_GS_CAN_CustomDeviceRequest(USBD_HandleTypeDef *pdev, USBD_SetupReqType
 				return true;
 
 			case 0x0005:
-				pbuf = USBD_MS_EXT_PROP_FEATURE_DESC;
-				len = sizeof(USBD_MS_EXT_PROP_FEATURE_DESC);
-				USBD_CtlSendData(pdev, pbuf, MIN(len, req->wLength));
-				return true;
+				if (req->wValue==0) { // only return our GUID for interface #0
+					pbuf = USBD_MS_EXT_PROP_FEATURE_DESC;
+					len = sizeof(USBD_MS_EXT_PROP_FEATURE_DESC);
+					USBD_CtlSendData(pdev, pbuf, MIN(len, req->wLength));
+					return true;
+				}
+				break;
 
 		}