diff --git a/firmware/atmel_softpack_libraries/libchip_sam3s/source/USBD_HAL.c b/firmware/atmel_softpack_libraries/libchip_sam3s/source/USBD_HAL.c
index 0eccc65d..ac2595cc 100644
--- a/firmware/atmel_softpack_libraries/libchip_sam3s/source/USBD_HAL.c
+++ b/firmware/atmel_softpack_libraries/libchip_sam3s/source/USBD_HAL.c
@@ -1077,6 +1077,14 @@ static inline uint8_t UDP_Read(uint8_t  bEndpoint,
  *      Exported functions
  *---------------------------------------------------------------------------*/
 
+
+uint16_t USBD_GetEndpointSize(uint8_t bEndpoint)
+{
+    Endpoint *pEndpoint = &(endpoints[bEndpoint]);
+
+    return pEndpoint->size;
+}
+
 /**
  * USBD (UDP) interrupt handler
  * Manages device resume, suspend, end of bus reset.
diff --git a/firmware/atmel_softpack_libraries/usb/include/USBD.h b/firmware/atmel_softpack_libraries/usb/include/USBD.h
index 15a68595..6fc931f1 100644
--- a/firmware/atmel_softpack_libraries/usb/include/USBD.h
+++ b/firmware/atmel_softpack_libraries/usb/include/USBD.h
@@ -214,6 +214,8 @@ typedef void (*MblTransferCallback)(void *pArg,
  *         Exported functions
  *------------------------------------------------------------------------------*/
 
+extern uint16_t USBD_GetEndpointSize(uint8_t bEndpoint);
+
 //extern void USBD_IrqHandler(void);
 
 extern void USBD_Init(void);
diff --git a/firmware/libcommon/source/host_communication.c b/firmware/libcommon/source/host_communication.c
index 0e496c54..9a6e5b32 100644
--- a/firmware/libcommon/source/host_communication.c
+++ b/firmware/libcommon/source/host_communication.c
@@ -33,10 +33,18 @@ static void usb_write_cb(uint8_t *arg, uint8_t status, uint32_t transferred,
 {
 	struct msgb *msg = (struct msgb *) arg;
 	struct usb_buffered_ep *bep = msg->dst;
+	uint16_t ep_size = USBD_GetEndpointSize(bep->ep);
 	unsigned long x;
 
 	TRACE_DEBUG("%s (EP=0x%02x)\r\n", __func__, bep->ep);
 
+	if (((msgb_length(msg) % ep_size) == 0) && (transferred == ep_size)) {
+		/* terminate with ZLP; pass in 'msg' again as 'arg' so we get
+		 * called the second time and proceed with usb_buf_free below */
+		USBD_Write(bep->ep, 0, 0, (TransferCallback) &usb_write_cb, msg);
+		return;
+	}
+
 	local_irq_save(x);
 	bep->in_progress--;
 	local_irq_restore(x);