diff --git a/src/XD0OTA.cpp b/src/XD0OTA.cpp
index fd6fcb5..c105696 100644
--- a/src/XD0OTA.cpp
+++ b/src/XD0OTA.cpp
@@ -17,6 +17,8 @@ String XD0OTA::getMAC() {
 
 void XD0OTA::update(void) {
 
+  setClock();
+
   int newVersion = checkForUpdates();
 
   if (newVersion < 1) {
@@ -33,10 +35,18 @@ void XD0OTA::update(void) {
     String fwImageURL = fwURL;
     fwImageURL.concat( ".bin" );
 
-  DEBUG_MSG( "Firmware image URL: " );
-  DEBUG_MSG( "%s\n", fwImageURL.c_str() );
+    DEBUG_MSG( "Firmware image URL: " );
+    DEBUG_MSG( "%s\n", fwImageURL.c_str() );
+
+    BearSSL::WiFiClientSecure client;
+    bool mfln = client.probeMaxFragmentLength("fwupdate.xd0.de", 444, 1024);
+    Serial.printf("MFLN supported: %s\n", mfln ? "yes" : "no");
+    if (mfln) {
+      client.setBufferSizes(1024, 1024);
+    }
+    client.setFingerprint(httpsFingerprint);
 
-    t_httpUpdate_return ret = ESPhttpUpdate.update( fwImageURL, String(FW_VERSION), httpsFingerprint );
+    t_httpUpdate_return ret = ESPhttpUpdate.update( client, fwImageURL, String(FW_VERSION) );
 
     switch(ret) {
         case HTTP_UPDATE_FAILED:
@@ -69,9 +79,12 @@ int XD0OTA::checkForUpdates() {
   DEBUG_MSG( "Firmware version URL: " );
   DEBUG_MSG( "%s\n", fwVersionURL.c_str() );
 
+  BearSSL::WiFiClientSecure client;
+  client.setFingerprint(httpsFingerprint);
+
   HTTPClient httpClient;
   httpClient.setTimeout(5000);
-  httpClient.begin( fwVersionURL, httpsFingerprint );
+  httpClient.begin( client, fwVersionURL );
   int httpCode = httpClient.GET();
   if( httpCode == 200 ) {
     String newFWVersion = httpClient.getString();
@@ -90,3 +103,21 @@ int XD0OTA::checkForUpdates() {
   httpClient.end();
   return newVersion;
 }
+
+void XD0OTA::setClock() {
+  configTime(0, 0, "pool.ntp.org", "time.nist.gov");  // UTC
+  DEBUG_MSG(F("Waiting for NTP time sync: "));
+  time_t now = time(nullptr);
+  while (now < 8 * 3600 * 2) {
+    yield();
+    delay(500);
+    DEBUG_MSG(F("."));
+    now = time(nullptr);
+  }
+
+  DEBUG_MSG(F(""));
+  struct tm timeinfo;
+  gmtime_r(&now, &timeinfo);
+  DEBUG_MSG(F("Current time: "));
+  Serial.print(asctime(&timeinfo));
+}
diff --git a/src/XD0OTA.h b/src/XD0OTA.h
index e1a77a6..97a4cdd 100644
--- a/src/XD0OTA.h
+++ b/src/XD0OTA.h
@@ -6,6 +6,8 @@
 #include <ESP8266HTTPClient.h>
 #include <ESP8266httpUpdate.h>
 
+#include <time.h>
+
 //const int FW_VERSION = 13; // see main.h
 
 class XD0OTA {
@@ -13,9 +15,10 @@ class XD0OTA {
     XD0OTA();
     void update(void);
     int checkForUpdates();
+    void setClock();
   private:
     const char* fwUrlBase = "https://fwupdate.xd0.de:444/fota/";
-    const char* httpsFingerprint = "37 42 61 B9 E6 EE 22 36 D1 59 67 7D 55 53 6E A4 C7 AA 60 26";
+    const uint8_t httpsFingerprint[20] = {0x37, 0x42, 0x61, 0xB9, 0xE6, 0xEE, 0x22, 0x36, 0xD1, 0x59, 0x67, 0x7D, 0x55, 0x53, 0x6E, 0xA4, 0xC7, 0xAA, 0x60, 0x26};
     String getMAC();
 };