diff --git a/ports/stm32/usbd_cdc_interface.c b/ports/stm32/usbd_cdc_interface.c
index a987646e7a..f6590ade52 100644
--- a/ports/stm32/usbd_cdc_interface.c
+++ b/ports/stm32/usbd_cdc_interface.c
@@ -165,7 +165,7 @@ void HAL_PCD_SOFCallback(PCD_HandleTypeDef *hpcd) {
         // doing other things and we must give it a chance to read our data.
         if (cdc->tx_buf_ptr_wait_count < 500) {
             USB_OTG_GlobalTypeDef *USBx = hpcd->Instance;
-            if (USBx_INEP(CDC_IN_EP & 0x7f)->DIEPTSIZ & USB_OTG_DIEPTSIZ_XFRSIZ) {
+            if (USBx_INEP(cdc->base.in_ep & 0x7f)->DIEPTSIZ & USB_OTG_DIEPTSIZ_XFRSIZ) {
                 // USB in-endpoint is still reading the data
                 cdc->tx_buf_ptr_wait_count++;
                 return;
diff --git a/ports/stm32/usbdev/class/inc/usbd_cdc_msc_hid.h b/ports/stm32/usbdev/class/inc/usbd_cdc_msc_hid.h
index 18c2c56c3c..b9671ef3a6 100644
--- a/ports/stm32/usbdev/class/inc/usbd_cdc_msc_hid.h
+++ b/ports/stm32/usbdev/class/inc/usbd_cdc_msc_hid.h
@@ -39,17 +39,13 @@
 #define MSC_IN_EP     (0x81)
 #define MSC_OUT_EP    (0x01)
 
-// Need to define here for usbd_cdc_interface.c (it needs CDC_IN_EP)
-#define CDC_IN_EP     (0x83)
-#define CDC_OUT_EP    (0x03)
-#define CDC_CMD_EP    (0x82)
-
 struct _usbd_cdc_msc_hid_state_t;
 
 typedef struct {
     struct _usbd_cdc_msc_hid_state_t *usbd; // The parent USB device
     uint32_t ctl_packet_buf[CDC_DATA_MAX_PACKET_SIZE / 4]; // Force 32-bit alignment
     uint8_t iface_num;
+    uint8_t in_ep;
     uint8_t cur_request;
     uint8_t cur_length;
     volatile uint8_t tx_in_progress;
diff --git a/ports/stm32/usbdev/class/src/usbd_cdc_msc_hid.c b/ports/stm32/usbdev/class/src/usbd_cdc_msc_hid.c
index 9ef92a1a6e..c2030043fb 100644
--- a/ports/stm32/usbdev/class/src/usbd_cdc_msc_hid.c
+++ b/ports/stm32/usbdev/class/src/usbd_cdc_msc_hid.c
@@ -61,6 +61,11 @@
 #define MSC_IFACE_NUM_WITH_CDC (0)
 #define HID_IFACE_NUM_WITH_CDC (0)
 #define HID_IFACE_NUM_WITH_MSC (1)
+
+#define CDC_IN_EP (0x83)
+#define CDC_OUT_EP (0x03)
+#define CDC_CMD_EP (0x82)
+
 #define HID_IN_EP_WITH_CDC (0x81)
 #define HID_OUT_EP_WITH_CDC (0x01)
 #define HID_IN_EP_WITH_MSC (0x83)
@@ -650,6 +655,10 @@ int USBD_SelectMode(usbd_cdc_msc_hid_state_t *usbd, uint32_t mode, USBD_HID_Mode
             return -1;
     }
 
+    if (usbd->usbd_mode & USBD_MODE_CDC) {
+        usbd->cdc->in_ep = CDC_IN_EP;
+    }
+
     // configure the HID descriptor, if needed
     if (usbd->usbd_mode & USBD_MODE_HID) {
         uint8_t *hid_desc = usbd->hid->desc;