diff --git a/platformio.ini b/platformio.ini
index 50dbd34a..9f056e50 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -10,10 +10,10 @@
 
 ; ---> SELECT TARGET PLATFORM HERE! <---
 [platformio]
-env_default = heltec_wifi_lora_32
+;env_default = heltec_wifi_lora_32
 ;env_default = ttgov1
 ;env_default = ttgov2
-;env_default = lopy
+env_default = lopy
 ;env_default = lopy4
 
 [env:heltec_wifi_lora_32]
@@ -91,8 +91,8 @@ lib_deps =
     ESP32 BLE Arduino@>=0.4.9
 build_flags = 
 ;set log level, we need build_flag for this, otherwise we can't use ESP_LOGx in arduino framework
-;   -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_VERBOSE
-    -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_NONE
+   -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_VERBOSE
+;    -DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_NONE
 ;needed for ESP32 BLE Ardunio v0.4.9
     -fexceptions
     -std=c++11
diff --git a/src/lorawan.cpp b/src/lorawan.cpp
index 85164280..e9169a06 100644
--- a/src/lorawan.cpp
+++ b/src/lorawan.cpp
@@ -53,7 +53,7 @@ void printKey(const char * name, const uint8_t * key, uint8_t len, bool lsb) {
   uint8_t start=lsb?len:0;
   uint8_t end = lsb?0:len;
   const uint8_t * p ;
-  char keystring[len+1] = "", keybyte[3];
+  char keystring[len+1] = "?", keybyte[3];
   for (uint8_t i=0; i<len ; i++) {
      p = lsb ? key+len-i-1 : key+i;
      sprintf(keybyte, "%02X", * p);