diff --git a/cores/arduino/USB/USBCore.cpp b/cores/arduino/USB/USBCore.cpp
index fb3046cb4..773d8fccd 100644
--- a/cores/arduino/USB/USBCore.cpp
+++ b/cores/arduino/USB/USBCore.cpp
@@ -454,7 +454,9 @@ void USBDeviceClass::initEP(uint32_t ep, uint32_t config)
 	}
 	else if (config == (USB_ENDPOINT_TYPE_BULK | USB_ENDPOINT_OUT(0)))
 	{
-		epHandlers[ep] = new DoubleBufferedEPOutHandler(usbd, ep, 256);
+		if (epHandlers[ep] == NULL) {
+			epHandlers[ep] = new DoubleBufferedEPOutHandler(usbd, ep, 256);
+		}
 	}
 	else if (config == (USB_ENDPOINT_TYPE_BULK | USB_ENDPOINT_IN(0)))
 	{