diff --git a/sonoff/_changelog.ino b/sonoff/_changelog.ino
index 72fe5d2aa..c78cddc9b 100644
--- a/sonoff/_changelog.ino
+++ b/sonoff/_changelog.ino
@@ -5,6 +5,7 @@
  * Add some MQTT housekeeping which might solve issue (#5755)
  * Add command SetOption65 0/1 and more Tuya Serial based device support (#5815)
  * Fix include of my_user_config.h in sonoff_aws_iot.cpp (#5930)
+ * Fix exception 9 when syslog is enabled and NTP is just synced (#5917)
  *
  * 6.5.0.14 20190602
  * Change webserver HTML input, button, textarea, and select name based on id
diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index da0c83db1..575776072 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -173,6 +173,7 @@ bool i2c_flg = false;                       // I2C configured
 bool spi_flg = false;                       // SPI configured
 bool soft_spi_flg = false;                  // Software SPI configured
 bool ntp_force_sync = false;                // Force NTP sync
+bool ntp_synced_message = false;            // NTP synced message flag
 myio my_module;                             // Active copy of Module GPIOs (17 x 8 bits)
 gpio_flag my_module_flag;                   // Active copy of Template GPIO flags
 StateBitfield global_state;                 // Global states (currently Wifi and Mqtt) (8 bits)
@@ -1995,6 +1996,12 @@ void PerformEverySecond(void)
 {
   uptime++;
 
+  if (ntp_synced_message) {
+    // Moved here to fix syslog UDP exception 9 during RtcSecond
+    AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_APPLICATION "(" D_UTC_TIME ") %s, (" D_DST_TIME ") %s, (" D_STD_TIME ") %s"), GetTime(0).c_str(), GetTime(2).c_str(), GetTime(3).c_str());
+    ntp_synced_message = false;
+  }
+
   if (BOOT_LOOP_TIME == uptime) {
     RtcReboot.fast_reboot_count = 0;
     RtcRebootSave();
diff --git a/sonoff/support.ino b/sonoff/support.ino
index 0bbd58ffe..ef04075a3 100644
--- a/sonoff/support.ino
+++ b/sonoff/support.ino
@@ -1503,7 +1503,7 @@ void Syslog(void)
     memmove(log_data + strlen(syslog_preamble), log_data, sizeof(log_data) - strlen(syslog_preamble));
     log_data[sizeof(log_data) -1] = '\0';
     memcpy(log_data, syslog_preamble, strlen(syslog_preamble));
-    PortUdp.write(log_data);
+    PortUdp.write(log_data, strlen(log_data));
     PortUdp.endPacket();
     delay(1);  // Add time for UDP handling (#5512)
   } else {
diff --git a/sonoff/support_rtc.ino b/sonoff/support_rtc.ino
index fd9575b32..03efeb510 100644
--- a/sonoff/support_rtc.ino
+++ b/sonoff/support_rtc.ino
@@ -365,7 +365,11 @@ void RtcSecond(void)
       RtcTime.year = tmpTime.year + 1970;
       daylight_saving_time = RuleToTime(Settings.tflag[1], RtcTime.year);
       standard_time = RuleToTime(Settings.tflag[0], RtcTime.year);
-      AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_APPLICATION "(" D_UTC_TIME ") %s, (" D_DST_TIME ") %s, (" D_STD_TIME ") %s"), GetTime(0).c_str(), GetTime(2).c_str(), GetTime(3).c_str());
+
+      // Do not use AddLog here if syslog is enabled. UDP will force exception 9
+//      AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_APPLICATION "(" D_UTC_TIME ") %s, (" D_DST_TIME ") %s, (" D_STD_TIME ") %s"), GetTime(0).c_str(), GetTime(2).c_str(), GetTime(3).c_str());
+      ntp_synced_message = true;
+
       if (local_time < 1451602800) {  // 2016-01-01
         rules_flag.time_init = 1;
       } else {