diff --git a/src/protocols/LoRaWAN/LoRaWAN.cpp b/src/protocols/LoRaWAN/LoRaWAN.cpp
index 392b46a8..88162099 100644
--- a/src/protocols/LoRaWAN/LoRaWAN.cpp
+++ b/src/protocols/LoRaWAN/LoRaWAN.cpp
@@ -968,8 +968,9 @@ int16_t LoRaWANNode::downlink(uint8_t* data, size_t* len) {
 
       isMACPayload = true;
       this->uplink(foptsBuff, foptsBufSize, RADIOLIB_LORAWAN_FPORT_MAC_COMMAND);
-      String strDown;
-      state = this->downlink(strDown);
+      uint8_t strDown[this->band->payloadLenMax[this->dataRates[RADIOLIB_LORAWAN_CHANNEL_DIR_DOWNLINK]]];
+      size_t lenDown = 0;
+      state = this->downlink(strDown, &lenDown);
       RADIOLIB_ASSERT(state);
     }