diff --git a/class/audio/usbd_audio.c b/class/audio/usbd_audio.c
index ad7b4c42..4478d459 100644
--- a/class/audio/usbd_audio.c
+++ b/class/audio/usbd_audio.c
@@ -68,7 +68,7 @@ static int audio_class_interface_request_handler(struct usb_setup_packet *setup,
     uint8_t ch;
     uint8_t mute;
     uint16_t volume;
-    int volume_db;
+    int volume_db = 0;
     uint32_t sampling_freq = 0;
 
     const char *mute_string[2] = { "off", "on" };
diff --git a/class/cdc/usbd_cdc.c b/class/cdc/usbd_cdc.c
index e9cbb503..297ddc7a 100644
--- a/class/cdc/usbd_cdc.c
+++ b/class/cdc/usbd_cdc.c
@@ -16,7 +16,6 @@ static int cdc_acm_class_interface_request_handler(struct usb_setup_packet *setu
                 setup->bRequest);
 
     struct cdc_line_coding line_coding;
-    struct cdc_line_coding line_coding_last;
     bool dtr, rts;
     uint8_t intf_num = LO_BYTE(setup->wIndex);
 
diff --git a/core/usbd_core.c b/core/usbd_core.c
index ea4afa94..9e8d00aa 100644
--- a/core/usbd_core.c
+++ b/core/usbd_core.c
@@ -68,8 +68,6 @@ USB_NOCACHE_RAM_SECTION struct usbd_core_priv {
     struct usbd_tx_rx_msg rx_msg[USB_EP_OUT_NUM];
 } g_usbd_core;
 
-usb_slist_t usbd_intf_head = USB_SLIST_OBJECT_INIT(usbd_intf_head);
-
 #if defined(CONFIG_USBDEV_TX_THREAD)
 usb_osal_mq_t usbd_tx_mq;
 usb_osal_thread_t usbd_tx_thread;
diff --git a/port/dwc2/usb_hc_dwc2.c b/port/dwc2/usb_hc_dwc2.c
index e88c76ab..bbad8420 100644
--- a/port/dwc2/usb_hc_dwc2.c
+++ b/port/dwc2/usb_hc_dwc2.c
@@ -501,8 +501,6 @@ int usb_hc_init(void)
     USB_OTG_GLB->GCCFG &= ~USB_OTG_GCCFG_VBUSBSEN;
     USB_OTG_GLB->GCCFG &= ~USB_OTG_GCCFG_VBUSASEN;
 #endif
-    /*!< FS/LS PHY clock select  */
-    USB_OTG_HOST->HCFG |= USB_OTG_HCFG_FSLSPCS_0;
 
     /* Set default Max speed support */
     USB_OTG_HOST->HCFG &= ~(USB_OTG_HCFG_FSLSS);