diff --git a/src/common/tusb_types.h b/src/common/tusb_types.h
index c37c19ba..70d0db94 100644
--- a/src/common/tusb_types.h
+++ b/src/common/tusb_types.h
@@ -139,6 +139,7 @@ typedef enum
   TUSB_REQ_RCPT_OTHER
 } tusb_request_recipient_t;
 
+// https://www.usb.org/defined-class-codes
 typedef enum
 {
   TUSB_CLASS_UNSPECIFIED          = 0    ,
@@ -176,6 +177,12 @@ typedef enum
   MISC_PROTOCOL_IAD = 1
 }misc_protocol_type_t;
 
+typedef enum
+{
+  APP_SUBCLASS_USBTMC = 0x03,
+  APP_SUBCLASS_DFU_RUNTIME = 0x01
+} app_subclass_type_t;
+
 typedef enum
 {
   DEVICE_CAPABILITY_WIRELESS_USB               = 0x01,
diff --git a/src/device/usbd.c b/src/device/usbd.c
index 9d15ea4a..06fe1f23 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -73,8 +73,11 @@ enum { DRVID_INVALID = 0xFFu };
 //--------------------------------------------------------------------+
 // Class Driver
 //--------------------------------------------------------------------+
-typedef struct {
+typedef struct
+{
   uint8_t class_code;
+  uint8_t subclass; // 0xFF support all values of subclass
+  uint8_t protocol; // 0xFF support all values of protocol
 
   void (* init             ) (void);
   void (* reset            ) (uint8_t rhport);
@@ -90,6 +93,9 @@ static usbd_class_driver_t const _usbd_driver[] =
   #if CFG_TUD_CDC
   {
       .class_code       = TUSB_CLASS_CDC,
+      .subclass         = CDC_COMM_SUBCLASS_ABSTRACT_CONTROL_MODEL,
+      .protocol         = 0xFF, // all protocols
+
       .init             = cdcd_init,
       .reset            = cdcd_reset,
       .open             = cdcd_open,
@@ -103,6 +109,9 @@ static usbd_class_driver_t const _usbd_driver[] =
   #if CFG_TUD_MSC
   {
       .class_code       = TUSB_CLASS_MSC,
+      .subclass         = MSC_SUBCLASS_SCSI,
+      .protocol         = MSC_PROTOCOL_BOT,
+
       .init             = mscd_init,
       .reset            = mscd_reset,
       .open             = mscd_open,
@@ -116,6 +125,9 @@ static usbd_class_driver_t const _usbd_driver[] =
   #if CFG_TUD_HID
   {
       .class_code       = TUSB_CLASS_HID,
+      .subclass         = 0xFF, // all subclass
+      .protocol         = 0xFF, // all protocol
+
       .init             = hidd_init,
       .reset            = hidd_reset,
       .open             = hidd_open,
@@ -129,6 +141,9 @@ static usbd_class_driver_t const _usbd_driver[] =
   #if CFG_TUD_MIDI
   {
       .class_code       = TUSB_CLASS_AUDIO,
+      .subclass         = AUDIO_SUBCLASS_CONTROL,
+      .protocol         = AUDIO_PROTOCOL_V1,
+
       .init             = midid_init,
       .open             = midid_open,
       .reset            = midid_reset,
@@ -142,6 +157,9 @@ static usbd_class_driver_t const _usbd_driver[] =
   #if CFG_TUD_VENDOR
   {
       .class_code       = TUSB_CLASS_VENDOR_SPECIFIC,
+      .subclass         = 0xFF, // all subclass
+      .protocol         = 0xFF, // all protocol
+
       .init             = vendord_init,
       .reset            = vendord_reset,
       .open             = vendord_open,
@@ -153,12 +171,11 @@ static usbd_class_driver_t const _usbd_driver[] =
   #endif
 
   #if CFG_TUD_USBTMC
-  // Presently USBTMC is the only defined class with the APP_SPECIFIC class code.
-  // We maybe need to add subclass codes here, or a callback to ask if a driver can
-  // handle a particular interface.
   {
-      .class_code       = TUD_USBTMC_APP_CLASS,
-    //.subclass_code    = TUD_USBTMC_APP_SUBCLASS
+      .class_code       = TUSB_CLASS_APPLICATION_SPECIFIC,
+      .subclass         = APP_SUBCLASS_USBTMC,
+      .protocol         = 0xFF, // all protocol
+
       .init             = usbtmcd_init_cb,
       .reset            = usbtmcd_reset_cb,
       .open             = usbtmcd_open_cb,
@@ -171,8 +188,10 @@ static usbd_class_driver_t const _usbd_driver[] =
 
   #if CFG_TUD_DFU_RT
   {
-      .class_code       = TUD_DFU_APP_CLASS,
-    //.subclass_code    = TUD_DFU_APP_SUBCLASS
+      .class_code       = TUSB_CLASS_APPLICATION_SPECIFIC,
+      .subclass         = APP_SUBCLASS_DFU_RUNTIME,
+      .protocol         = DFU_PROTOCOL_RT,
+
       .init             = dfu_rtd_init,
       .reset            = dfu_rtd_reset,
       .open             = dfu_rtd_open,
@@ -183,11 +202,14 @@ static usbd_class_driver_t const _usbd_driver[] =
   },
   #endif
 
-  #if CFG_TUD_NET
-#if CFG_TUD_NET != OPT_NET_EEM
+#if CFG_TUD_NET
+  #if CFG_TUD_NET != OPT_NET_EEM
   /* RNDIS management interface */
   {
       .class_code       = TUD_RNDIS_ITF_CLASS,
+      .subclass         = TUD_RNDIS_ITF_SUBCLASS,
+      .protocol         = TUD_RNDIS_ITF_PROTOCOL,
+
       .init             = netd_init,
       .reset            = netd_reset,
       .open             = netd_open,
@@ -196,10 +218,14 @@ static usbd_class_driver_t const _usbd_driver[] =
       .xfer_cb          = netd_xfer_cb,
       .sof              = NULL,
   },
-#endif
+  #endif
+
   /* CDC-ECM management interface; CDC-EEM data interface */
   {
       .class_code       = TUSB_CLASS_CDC,
+      .subclass         = CDC_COMM_SUBCLASS_ETHERNET_NETWORKING_CONTROL_MODEL,
+      .protocol         = 0x00,
+
       .init             = netd_init,
       .reset            = netd_reset,
 #if CFG_TUD_NET == OPT_NET_EEM
@@ -212,10 +238,14 @@ static usbd_class_driver_t const _usbd_driver[] =
       .xfer_cb          = netd_xfer_cb,
       .sof              = NULL,
   },
+
   /* RNDIS/CDC-ECM data interface */
-#if CFG_TUD_NET != OPT_NET_EEM
+  #if CFG_TUD_NET != OPT_NET_EEM
   {
       .class_code       = TUSB_CLASS_CDC_DATA,
+      .subclass         = 0x00,
+      .protocol         = 0x00,
+
       .init             = netd_init_data,
       .reset            = NULL,
       .open             = netd_open_data,
@@ -224,8 +254,8 @@ static usbd_class_driver_t const _usbd_driver[] =
       .xfer_cb          = netd_xfer_cb,
       .sof              = NULL,
   },
-#endif
   #endif
+#endif
 };
 
 enum { USBD_CLASS_DRIVER_COUNT = TU_ARRAY_SIZE(_usbd_driver) };
diff --git a/src/device/usbd.h b/src/device/usbd.h
index dbc94bc3..7b04ef9a 100644
--- a/src/device/usbd.h
+++ b/src/device/usbd.h
@@ -291,23 +291,23 @@ TU_ATTR_WEAK bool tud_vendor_control_complete_cb(uint8_t rhport, tusb_control_re
 //   Interface number, number of endpoints, EP string index, USB_TMC_PROTOCOL*, bulk-out endpoint ID,
 //   bulk-in endpoint ID
 #define TUD_USBTMC_IF_DESCRIPTOR(_itfnum, _bNumEndpoints, _stridx, _itfProtocol) \
-/* Interface */ \
+  /* Interface */ \
   0x09, TUSB_DESC_INTERFACE, _itfnum, 0x00, _bNumEndpoints, TUD_USBTMC_APP_CLASS, TUD_USBTMC_APP_SUBCLASS, _itfProtocol, _stridx
 
 #define TUD_USBTMC_IF_DESCRIPTOR_LEN 9u
 
 #define TUD_USBTMC_BULK_DESCRIPTORS(_epout, _epin, _bulk_epsize) \
-/* Endpoint Out */ \
-7, TUSB_DESC_ENDPOINT, _epout, TUSB_XFER_BULK, U16_TO_U8S_LE(_bulk_epsize), 0u, \
-/* Endpoint In */ \
-7, TUSB_DESC_ENDPOINT, _epin, TUSB_XFER_BULK, U16_TO_U8S_LE(_bulk_epsize), 0u
+  /* Endpoint Out */ \
+  7, TUSB_DESC_ENDPOINT, _epout, TUSB_XFER_BULK, U16_TO_U8S_LE(_bulk_epsize), 0u, \
+  /* Endpoint In */ \
+  7, TUSB_DESC_ENDPOINT, _epin, TUSB_XFER_BULK, U16_TO_U8S_LE(_bulk_epsize), 0u
 
 #define TUD_USBTMC_BULK_DESCRIPTORS_LEN (7u+7u)
 
 /* optional interrupt endpoint */ \
 // _int_pollingInterval : for LS/FS, expressed in frames (1ms each). 16 may be a good number?
 #define TUD_USBTMC_INT_DESCRIPTOR(_ep_interrupt, _ep_interrupt_size, _int_pollingInterval ) \
-7, TUSB_DESC_ENDPOINT, _ep_interrupt, TUSB_XFER_INTERRUPT, U16_TO_U8S_LE(_ep_interrupt_size), 0x16
+  7, TUSB_DESC_ENDPOINT, _ep_interrupt, TUSB_XFER_INTERRUPT, U16_TO_U8S_LE(_ep_interrupt_size), 0x16
 
 #define TUD_USBTMC_INT_DESCRIPTOR_LEN (7u)
 
@@ -377,7 +377,7 @@ TU_ATTR_WEAK bool tud_vendor_control_complete_cb(uint8_t rhport, tusb_control_re
   #define TUD_RNDIS_ITF_PROTOCOL 0xFF /* CDC_COMM_PROTOCOL_MICROSOFT_RNDIS */
 #else
   /* Windows 7+ */
-  #define TUD_RNDIS_ITF_CLASS    0xE0
+  #define TUD_RNDIS_ITF_CLASS    TUSB_CLASS_WIRELESS_CONTROLLER
   #define TUD_RNDIS_ITF_SUBCLASS 0x01
   #define TUD_RNDIS_ITF_PROTOCOL 0x03
 #endif