diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 12c45391..31dcf040 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -162,9 +162,14 @@ jobs:
               # skip sketch
               echo -e "\n\033[1;33mSkipped ${example##*/} (matched with ${{ steps.prep.outputs.skip-pattern }})\033[0m";
             else
+              # apply special flags for LoRaWAN
+              if [[ ${example} =~ "LoRaWAN" ]]; then
+                flags="-DRADIOLIB_LORAWAN_DEV_ADDR=0 -DRADIOLIB_LORAWAN_NWKS_KEY=0 -DRADIOLIB_LORAWAN_SNWKSINT_KEY=0 -DRADIOLIB_LORAWAN_NWKSENC_KEY=0 -DRADIOLIB_LORAWAN_APPS_KEY=0 -DRADIOLIB_LORAWAN_APP_KEY=0 -DRADIOLIB_LORAWAN_NWK_KEY=0 -DRADIOLIB_LORAWAN_DEV_EUI=0 -DARDUINO_TTGO_LORA32_V1"
+              fi
+
               # build sketch
               echo -e "\n\033[1;33mBuilding ${example##*/} ... \033[0m";
-              arduino-cli compile --libraries /home/runner/work/RadioLib --fqbn ${{ matrix.id }}${{ steps.prep.outputs.options }} $example --warnings=${{ steps.prep.outputs.warnings }}
+              arduino-cli compile --libraries /home/runner/work/RadioLib --fqbn ${{ matrix.id }}${{ steps.prep.outputs.options }} --build-property compiler.cpp.extra_flags="$flags" $example --warnings=${{ steps.prep.outputs.warnings }}
               if [ $? -ne 0 ]; then
                 echo -e "\033[1;31m${example##*/} build FAILED\033[0m\n";
                 exit 1;
diff --git a/examples/LoRaWAN/LoRaWAN_ABP/configABP.h b/examples/LoRaWAN/LoRaWAN_ABP/configABP.h
index 33fd9fa0..5d8d29e1 100644
--- a/examples/LoRaWAN/LoRaWAN_ABP/configABP.h
+++ b/examples/LoRaWAN/LoRaWAN_ABP/configABP.h
@@ -125,8 +125,10 @@ void debug(bool isFail, const __FlashStringHelper* message, int state, bool Free
 
 // Helper function to display a byte array
 void arrayDump(uint8_t *buffer, uint16_t len) {
-  for (uint16_t c; c < len; c++) {
-    Serial.printf("%02X", buffer[c]);
+  for(uint16_t c = 0; c < len; c++) {
+    char b = buffer[c];
+    if(b < 0x10) { Serial.print('0'); }
+    Serial.print(b, HEX);
   }
   Serial.println();
 }
diff --git a/examples/LoRaWAN/LoRaWAN_Reference/config.h b/examples/LoRaWAN/LoRaWAN_Reference/config.h
index bba38e4f..b9c1bf71 100644
--- a/examples/LoRaWAN/LoRaWAN_Reference/config.h
+++ b/examples/LoRaWAN/LoRaWAN_Reference/config.h
@@ -120,8 +120,10 @@ void debug(bool isFail, const __FlashStringHelper* message, int state, bool Free
 
 // Helper function to display a byte array
 void arrayDump(uint8_t *buffer, uint16_t len) {
-  for (uint16_t c; c < len; c++) {
-    Serial.printf("%02X", buffer[c]);
+  for(uint16_t c = 0; c < len; c++) {
+    char b = buffer[c];
+    if(b < 0x10) { Serial.print('0'); }
+    Serial.print(b, HEX);
   }
   Serial.println();
 }
diff --git a/examples/LoRaWAN/LoRaWAN_Starter/config.h b/examples/LoRaWAN/LoRaWAN_Starter/config.h
index bba38e4f..b9c1bf71 100644
--- a/examples/LoRaWAN/LoRaWAN_Starter/config.h
+++ b/examples/LoRaWAN/LoRaWAN_Starter/config.h
@@ -120,8 +120,10 @@ void debug(bool isFail, const __FlashStringHelper* message, int state, bool Free
 
 // Helper function to display a byte array
 void arrayDump(uint8_t *buffer, uint16_t len) {
-  for (uint16_t c; c < len; c++) {
-    Serial.printf("%02X", buffer[c]);
+  for(uint16_t c = 0; c < len; c++) {
+    char b = buffer[c];
+    if(b < 0x10) { Serial.print('0'); }
+    Serial.print(b, HEX);
   }
   Serial.println();
 }