diff --git a/src/platform/nrf52/NRF52Bluetooth.cpp b/src/platform/nrf52/NRF52Bluetooth.cpp
index 0347c2b02..acb26071f 100644
--- a/src/platform/nrf52/NRF52Bluetooth.cpp
+++ b/src/platform/nrf52/NRF52Bluetooth.cpp
@@ -244,6 +244,7 @@ void NRF52Bluetooth::setup()
     Bluefruit.Periph.setConnectCallback(onConnect);
     Bluefruit.Periph.setDisconnectCallback(onDisconnect);
 
+    bledfu.setPermission(SECMODE_ENC_WITH_MITM, SECMODE_ENC_WITH_MITM);
     bledfu.begin(); // Install the DFU helper
     
     // Configure and Start the Device Information Service