diff --git a/src/main/vcp_hal/usbd_cdc_interface.c b/src/main/vcp_hal/usbd_cdc_interface.c
index 4d39821882..529a327ce2 100644
--- a/src/main/vcp_hal/usbd_cdc_interface.c
+++ b/src/main/vcp_hal/usbd_cdc_interface.c
@@ -61,6 +61,8 @@
 #define APP_RX_DATA_SIZE  2048
 #define APP_TX_DATA_SIZE  2048
 
+#define APP_TX_BLOCK_SIZE 512
+
 /* Private macro -------------------------------------------------------------*/
 /* Private variables ---------------------------------------------------------*/
 USBD_CDC_LineCodingTypeDef LineCoding =
@@ -241,35 +243,42 @@ static int8_t CDC_Itf_Control (uint8_t cmd, uint8_t* pbuf, uint16_t length)
   */
 void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
 {
-    if (htim->Instance != TIMusb) return;
+    if (htim->Instance != TIMusb) {
+        return;
+    }
 
-    uint32_t buffptr;
     uint32_t buffsize;
+    static uint32_t lastBuffsize = 0;
 
-    if (UserTxBufPtrOut != UserTxBufPtrIn)
-    {
-        if (UserTxBufPtrOut > UserTxBufPtrIn) /* Roll-back */
-        {
-            buffsize = APP_RX_DATA_SIZE - UserTxBufPtrOut;
-        }
-        else
-        {
-            buffsize = UserTxBufPtrIn - UserTxBufPtrOut;
-        }
+    USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)USBD_Device.pCDC_ClassData;
 
-        buffptr = UserTxBufPtrOut;
-
-        USBD_CDC_SetTxBuffer(&USBD_Device, (uint8_t*)&UserTxBuffer[buffptr], buffsize);
-
-        if (USBD_CDC_TransmitPacket(&USBD_Device) == USBD_OK)
-        {
-            UserTxBufPtrOut += buffsize;
-            if (UserTxBufPtrOut == APP_TX_DATA_SIZE)
-            {
+    if (hcdc->TxState == 0) {
+        // endpoint has finished transmitting previous block
+        if (lastBuffsize) {
+            // move the ring buffer tail based on the previous succesful transmission
+            UserTxBufPtrOut += lastBuffsize;
+            if (UserTxBufPtrOut == APP_TX_DATA_SIZE) {
                 UserTxBufPtrOut = 0;
             }
+            lastBuffsize = 0;
         }
-    }
+        if (UserTxBufPtrOut != UserTxBufPtrIn) {
+            if (UserTxBufPtrOut > UserTxBufPtrIn) { /* Roll-back */
+                buffsize = APP_TX_DATA_SIZE - UserTxBufPtrOut;
+            } else {
+                buffsize = UserTxBufPtrIn - UserTxBufPtrOut;
+            }
+            if (buffsize > APP_TX_BLOCK_SIZE) {
+                buffsize = APP_TX_BLOCK_SIZE;
+            }
+
+            USBD_CDC_SetTxBuffer(&USBD_Device, (uint8_t*)&UserTxBuffer[UserTxBufPtrOut], buffsize);
+
+            if (USBD_CDC_TransmitPacket(&USBD_Device) == USBD_OK) {
+                lastBuffsize = buffsize;
+            }
+        }
+    } 
 }
 
 /**
@@ -379,16 +388,13 @@ uint32_t CDC_Send_FreeBytes(void)
  */
 uint32_t CDC_Send_DATA(const uint8_t *ptrBuffer, uint32_t sendLength)
 {
-    USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)USBD_Device.pCDC_ClassData;
-    while (hcdc->TxState != 0);
-
-    for (uint32_t i = 0; i < sendLength; i++)
-    {
-        UserTxBuffer[UserTxBufPtrIn] = ptrBuffer[i];
-        UserTxBufPtrIn = (UserTxBufPtrIn + 1) % APP_TX_DATA_SIZE;
+    for (uint32_t i = 0; i < sendLength; i++) {
         while (CDC_Send_FreeBytes() == 0) {
+            // block until there is free space in the ring buffer
             delay(1);
         }
+        UserTxBuffer[UserTxBufPtrIn] = ptrBuffer[i];
+        UserTxBufPtrIn = (UserTxBufPtrIn + 1) % APP_TX_DATA_SIZE;
     }
     return sendLength;
 }
diff --git a/src/main/vcp_hal/usbd_cdc_interface.h b/src/main/vcp_hal/usbd_cdc_interface.h
index 3674dc410f..f7f0aa20f6 100644
--- a/src/main/vcp_hal/usbd_cdc_interface.h
+++ b/src/main/vcp_hal/usbd_cdc_interface.h
@@ -65,7 +65,7 @@
 
 /* Periodically, the state of the buffer "UserTxBuffer" is checked.
    The period depends on CDC_POLLING_INTERVAL */
-#define CDC_POLLING_INTERVAL             10 /* in ms. The max is 65 and the min is 1 */
+#define CDC_POLLING_INTERVAL             5 /* in ms. The max is 65 and the min is 1 */
 
 /* Exported typef ------------------------------------------------------------*/
 /* The following structures groups all needed parameters to be configured for the