diff --git a/README.md b/README.md
index 910ce69e..a3fb586b 100644
--- a/README.md
+++ b/README.md
@@ -93,7 +93,7 @@ If your device has a **real time clock** it can be updated bei either LoRaWAN ne
 
 # Building
 
-Use <A HREF="https://platformio.org/">PlatformIO</A> with your preferred IDE for development and building this code. Make sure you have latest PlatformIO version.
+Use <A HREF="https://platformio.org/">PlatformIO</A> with your preferred IDE for development and building this code. Make sure you have latest PlatformIO version, **at least v4.0.0a15**.
 
 # Uploading
 
diff --git a/platformio.ini b/platformio.ini
index 81188a3c..8cde83eb 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -74,7 +74,10 @@ build_flags_basic =
     -include "src/hal/${PIOENV}.h"
     -include "src/paxcounter.conf"
     -w
-    '-DARDUINO_LMIC_PROJECT_CONFIG_H=../../../src/lmic_config.h'
+    ;use this is you have platformio version >= 4.0.0a15
+    '-DARDUINO_LMIC_PROJECT_CONFIG_H=../../../../../src/lmic_config.h'
+    ;use this is you have platformio version < 4.0.0a15
+    ;'-DARDUINO_LMIC_PROJECT_CONFIG_H=../../../src/lmic_config.h'
     '-DCORE_DEBUG_LEVEL=${common.debug_level}'
     '-DLOG_LOCAL_LEVEL=${common.debug_level}'
     '-DBINTRAY_PACKAGE="${PIOENV}"'
diff --git a/src/hal/lolin32lite.h b/src/hal/lolin32lite.h
index 70dfbcdf..3c3942e8 100644
--- a/src/hal/lolin32lite.h
+++ b/src/hal/lolin32lite.h
@@ -7,9 +7,10 @@
 
 // Hardware related definitions for lolin32lite (without LoRa shield)
 
-#define HAS_LORA 0          // no LoRa module
-#define CFG_sx1272_radio 1  // dummy
 #define HAS_LED LED_BUILTIN // on board LED on GPIO5
 #define LED_ACTIVE_LOW 1    // Onboard LED is active when pin is LOW
 
-#endif
+// disable brownout detection (avoid unexpected reset on some boards)
+#define DISABLE_BROWNOUT 1 // comment out if you want to keep brownout feature
+
+#endif
\ No newline at end of file
diff --git a/src/hal/wemos32oled.h b/src/hal/wemos32oled.h
index d5c27832..3917dfea 100644
--- a/src/hal/wemos32oled.h
+++ b/src/hal/wemos32oled.h
@@ -40,6 +40,6 @@
 // user defined sensors (if connected)
 //#define HAS_SENSORS 1 // comment out if device has user defined sensors
 
-//#define DISABLE_BROWNOUT 1 // comment out if you want to keep brownout feature
+#define DISABLE_BROWNOUT 1 // comment out if you want to keep brownout feature
 
 #endif
diff --git a/src/main.cpp b/src/main.cpp
index a26379fc..ca10932c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -300,7 +300,7 @@ void setup() {
 #endif
 
 #if (VENDORFILTER)
-  strcat_P(features, " OUIFLT");
+  strcat_P(features, " FILTER");
 #endif
 
 // initialize display
diff --git a/src/mbedtls_aes.c b/src/mbedtls_aes.c
index aa481790..23b18a06 100644
--- a/src/mbedtls_aes.c
+++ b/src/mbedtls_aes.c
@@ -10,10 +10,10 @@
  * AES encryption using ESP32's hardware AES unit.
  *******************************************************************************/
 
-#include "mbedtls/aes.h"
-#include "lmic/oslmic.h"
+#ifdef USE_MBEDTLS_AES
 
-#if defined USE_MBEDTLS_AES
+#include "mbedtls/aes.h"
+#include "../../lmic/oslmic.h"
 
 void lmic_aes_encrypt(u1_t *data, u1_t *key)
 {