diff --git a/firmware/libcommon/source/host_communication.c b/firmware/libcommon/source/host_communication.c
index 0e496c5..9a6e5b3 100644
--- a/firmware/libcommon/source/host_communication.c
+++ b/firmware/libcommon/source/host_communication.c
@@ -33,10 +33,18 @@
 {
 	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);