diff --git a/ports/stm32/usbd_desc.c b/ports/stm32/usbd_desc.c
index 09e1608c84..8b8e7e7f0f 100644
--- a/ports/stm32/usbd_desc.c
+++ b/ports/stm32/usbd_desc.c
@@ -111,7 +111,7 @@ void USBD_SetVIDPIDRelease(uint16_t vid, uint16_t pid, uint16_t device_release_n
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_DeviceDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
+STATIC uint8_t *USBD_DeviceDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
     *length = sizeof(hUSBDDeviceDesc);
     return hUSBDDeviceDesc;
 }
@@ -122,7 +122,7 @@ STATIC uint8_t *USBD_DeviceDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_LangIDStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
+STATIC uint8_t *USBD_LangIDStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
     *length = sizeof(USBD_LangIDDesc);
     return USBD_LangIDDesc;
 }
@@ -133,8 +133,8 @@ STATIC uint8_t *USBD_LangIDStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *leng
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_ProductStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
-    if(speed == 0) {
+STATIC uint8_t *USBD_ProductStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
+    if (pdev->dev_speed == USBD_SPEED_HIGH) {
         USBD_GetString((uint8_t *)USBD_PRODUCT_HS_STRING, USBD_StrDesc, length);
     } else {
         USBD_GetString((uint8_t *)USBD_PRODUCT_FS_STRING, USBD_StrDesc, length);
@@ -148,7 +148,7 @@ STATIC uint8_t *USBD_ProductStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *len
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
+STATIC uint8_t *USBD_ManufacturerStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
     USBD_GetString((uint8_t *)USBD_MANUFACTURER_STRING, USBD_StrDesc, length);
     return USBD_StrDesc;
 }
@@ -159,7 +159,7 @@ STATIC uint8_t *USBD_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_SerialStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
+STATIC uint8_t *USBD_SerialStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
     // This document: http://www.usb.org/developers/docs/devclass_docs/usbmassbulk_10.pdf
     // says that the serial number has to be at least 12 digits long and that
     // the last 12 digits need to be unique. It also stipulates that the valid
@@ -189,8 +189,8 @@ STATIC uint8_t *USBD_SerialStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *leng
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_ConfigStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
-    if(speed == USBD_SPEED_HIGH) {
+STATIC uint8_t *USBD_ConfigStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
+    if (pdev->dev_speed == USBD_SPEED_HIGH) {
         USBD_GetString((uint8_t *)USBD_CONFIGURATION_HS_STRING, USBD_StrDesc, length);
     } else {
         USBD_GetString((uint8_t *)USBD_CONFIGURATION_FS_STRING, USBD_StrDesc, length);
@@ -204,8 +204,8 @@ STATIC uint8_t *USBD_ConfigStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *leng
   * @param  length: Pointer to data length variable
   * @retval Pointer to descriptor buffer
   */
-STATIC uint8_t *USBD_InterfaceStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length) {
-    if(speed == 0) {
+STATIC uint8_t *USBD_InterfaceStrDescriptor(USBD_HandleTypeDef *pdev, uint16_t *length) {
+    if (pdev->dev_speed == USBD_SPEED_HIGH) {
         USBD_GetString((uint8_t *)USBD_INTERFACE_HS_STRING, USBD_StrDesc, length);
     } else {
         USBD_GetString((uint8_t *)USBD_INTERFACE_FS_STRING, USBD_StrDesc, length);
diff --git a/ports/stm32/usbdev/core/inc/usbd_def.h b/ports/stm32/usbdev/core/inc/usbd_def.h
index bd913a2865..888d426ef3 100644
--- a/ports/stm32/usbdev/core/inc/usbd_def.h
+++ b/ports/stm32/usbdev/core/inc/usbd_def.h
@@ -193,16 +193,18 @@ typedef enum {
   USBD_FAIL,
 }USBD_StatusTypeDef;
 
+struct _USBD_HandleTypeDef;
+
 /* USB Device descriptors structure */
 typedef struct
 {
-  uint8_t  *(*GetDeviceDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);  
-  uint8_t  *(*GetLangIDStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length); 
-  uint8_t  *(*GetManufacturerStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);  
-  uint8_t  *(*GetProductStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);  
-  uint8_t  *(*GetSerialStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);  
-  uint8_t  *(*GetConfigurationStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);  
-  uint8_t  *(*GetInterfaceStrDescriptor)( USBD_SpeedTypeDef speed , uint16_t *length);   
+  uint8_t *(*GetDeviceDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetLangIDStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetManufacturerStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetProductStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetSerialStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetConfigurationStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
+  uint8_t *(*GetInterfaceStrDescriptor)(struct _USBD_HandleTypeDef *pdev, uint16_t *length);
 } USBD_DescriptorsTypeDef;
 
 /* USB Device handle structure */
diff --git a/ports/stm32/usbdev/core/src/usbd_ctlreq.c b/ports/stm32/usbdev/core/src/usbd_ctlreq.c
index 15d9b6ec49..5fba322fa6 100644
--- a/ports/stm32/usbdev/core/src/usbd_ctlreq.c
+++ b/ports/stm32/usbdev/core/src/usbd_ctlreq.c
@@ -330,7 +330,7 @@ static void USBD_GetDescriptor(USBD_HandleTypeDef *pdev ,
   switch (req->wValue >> 8)
   {
   case USB_DESC_TYPE_DEVICE:
-    pbuf = pdev->pDesc->GetDeviceDescriptor(pdev->dev_speed, &len);
+    pbuf = pdev->pDesc->GetDeviceDescriptor(pdev, &len);
     break;
     
   case USB_DESC_TYPE_CONFIGURATION:     
@@ -350,27 +350,27 @@ static void USBD_GetDescriptor(USBD_HandleTypeDef *pdev ,
     switch ((uint8_t)(req->wValue))
     {
     case USBD_IDX_LANGID_STR:
-     pbuf = pdev->pDesc->GetLangIDStrDescriptor(pdev->dev_speed, &len);        
+     pbuf = pdev->pDesc->GetLangIDStrDescriptor(pdev, &len);        
       break;
       
     case USBD_IDX_MFC_STR:
-      pbuf = pdev->pDesc->GetManufacturerStrDescriptor(pdev->dev_speed, &len);
+      pbuf = pdev->pDesc->GetManufacturerStrDescriptor(pdev, &len);
       break;
       
     case USBD_IDX_PRODUCT_STR:
-      pbuf = pdev->pDesc->GetProductStrDescriptor(pdev->dev_speed, &len);
+      pbuf = pdev->pDesc->GetProductStrDescriptor(pdev, &len);
       break;
       
     case USBD_IDX_SERIAL_STR:
-      pbuf = pdev->pDesc->GetSerialStrDescriptor(pdev->dev_speed, &len);
+      pbuf = pdev->pDesc->GetSerialStrDescriptor(pdev, &len);
       break;
       
     case USBD_IDX_CONFIG_STR:
-      pbuf = pdev->pDesc->GetConfigurationStrDescriptor(pdev->dev_speed, &len);
+      pbuf = pdev->pDesc->GetConfigurationStrDescriptor(pdev, &len);
       break;
       
     case USBD_IDX_INTERFACE_STR:
-      pbuf = pdev->pDesc->GetInterfaceStrDescriptor(pdev->dev_speed, &len);
+      pbuf = pdev->pDesc->GetInterfaceStrDescriptor(pdev, &len);
       break;
       
     default: