diff --git a/src/class/cdc/cdc_device.c b/src/class/cdc/cdc_device.c
index 2e0a0c30d..e856963f5 100644
--- a/src/class/cdc/cdc_device.c
+++ b/src/class/cdc/cdc_device.c
@@ -47,6 +47,7 @@
 
 typedef struct
 {
+  uint8_t rhport;
   uint8_t itf_num;
   uint8_t ep_notif;
   uint8_t ep_in;
@@ -84,7 +85,6 @@ CFG_TUD_MEM_SECTION tu_static cdcd_interface_t _cdcd_itf[CFG_TUD_CDC];
 
 static bool _prep_out_transaction (cdcd_interface_t* p_cdc)
 {
-  uint8_t const rhport = 0;
   uint16_t available = tu_fifo_remaining(&p_cdc->rx_ff);
 
   // Prepare for incoming data but only allow what we can store in the ring buffer.
@@ -94,18 +94,18 @@ static bool _prep_out_transaction (cdcd_interface_t* p_cdc)
   TU_VERIFY(available >= sizeof(p_cdc->epout_buf));
 
   // claim endpoint
-  TU_VERIFY(usbd_edpt_claim(rhport, p_cdc->ep_out));
+  TU_VERIFY(usbd_edpt_claim(p_cdc->rhport, p_cdc->ep_out));
 
   // fifo can be changed before endpoint is claimed
   available = tu_fifo_remaining(&p_cdc->rx_ff);
 
   if ( available >= sizeof(p_cdc->epout_buf) )
   {
-    return usbd_edpt_xfer(rhport, p_cdc->ep_out, p_cdc->epout_buf, sizeof(p_cdc->epout_buf));
+    return usbd_edpt_xfer(p_cdc->rhport, p_cdc->ep_out, p_cdc->epout_buf, sizeof(p_cdc->epout_buf));
   }else
   {
     // Release endpoint since we don't make any transfer
-    usbd_edpt_release(rhport, p_cdc->ep_out);
+    usbd_edpt_release(p_cdc->rhport, p_cdc->ep_out);
 
     return false;
   }
@@ -135,7 +135,6 @@ void tud_cdc_n_set_wanted_char (uint8_t itf, char wanted)
   _cdcd_itf[itf].wanted_char = wanted;
 }
 
-
 //--------------------------------------------------------------------+
 // READ API
 //--------------------------------------------------------------------+
@@ -194,23 +193,21 @@ uint32_t tud_cdc_n_write_flush (uint8_t itf)
   // No data to send
   if ( !tu_fifo_count(&p_cdc->tx_ff) ) return 0;
 
-  uint8_t const rhport = 0;
-
   // Claim the endpoint
-  TU_VERIFY( usbd_edpt_claim(rhport, p_cdc->ep_in), 0 );
+  TU_VERIFY( usbd_edpt_claim(p_cdc->rhport, p_cdc->ep_in), 0 );
 
   // Pull data from FIFO
   uint16_t const count = tu_fifo_read_n(&p_cdc->tx_ff, p_cdc->epin_buf, sizeof(p_cdc->epin_buf));
 
   if ( count )
   {
-    TU_ASSERT( usbd_edpt_xfer(rhport, p_cdc->ep_in, p_cdc->epin_buf, count), 0 );
+    TU_ASSERT( usbd_edpt_xfer(p_cdc->rhport, p_cdc->ep_in, p_cdc->epin_buf, count), 0 );
     return count;
   }else
   {
     // Release endpoint since we don't make any transfer
     // Note: data is dropped if terminal is not connected
-    usbd_edpt_release(rhport, p_cdc->ep_in);
+    usbd_edpt_release(p_cdc->rhport, p_cdc->ep_in);
     return 0;
   }
 }
@@ -319,6 +316,7 @@ uint16_t cdcd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint1
   TU_ASSERT(p_cdc, 0);
 
   //------------- Control Interface -------------//
+  p_cdc->rhport = rhport;
   p_cdc->itf_num = itf_desc->bInterfaceNumber;
 
   uint16_t drv_len = sizeof(tusb_desc_interface_t);