diff --git a/.travis.yml b/.travis.yml
index a05bcc2..2a15183 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,7 +16,8 @@ before_install:
   - sudo mv AsyncTCP-master /usr/local/share/arduino/libraries/AsyncTCP
 
 install:
-  - arduino --install-boards esp32:esp32
+  - arduino --pref "boardsmanager.additional.urls=https://dl.espressif.com/dl/package_esp32_index.json" --save-prefs
+  - arduino --install-boards esp32:esp32 --safe-prefs
   - ln -s $PWD/libraries/SondeLib /usr/local/share/arduino/libraries/SondeLib
   - ln -s $PWD/libraries/SX1278FSK /usr/local/share/arduino/libraries/SX1278FSK
   - arduino --install-library "U8g2"
diff --git a/RX_FSK/RX_FSK.ino b/RX_FSK/RX_FSK.ino
index 741c08d..fb44735 100644
--- a/RX_FSK/RX_FSK.ino
+++ b/RX_FSK/RX_FSK.ino
@@ -1102,7 +1102,8 @@ void loopWifiScan() {
 }
 
 void loop() {
-  Serial.println("Running main loop");
+  Serial.print("Running main loop. free heap:");
+  Serial.println(ESP.getFreeHeap());
   switch (mainState) {
     case ST_DECODER: loopDecoder(); break;
     case ST_SCANNER: loopScanner(); break;