diff --git a/lib/JsonMqttHandler/src/JsonMqttHandler.cpp b/lib/JsonMqttHandler/src/JsonMqttHandler.cpp
index d78069e6..a897f01d 100644
--- a/lib/JsonMqttHandler/src/JsonMqttHandler.cpp
+++ b/lib/JsonMqttHandler/src/JsonMqttHandler.cpp
@@ -96,7 +96,8 @@ bool JsonMqttHandler::publishList1(AmsData* data, EnergyAccounting* ea) {
     }
     pos += snprintf_P(json+pos, BufferSize-pos, PSTR("\"P\":%d"), data->getActiveImportPower());
     pos += appendJsonFooter(ea, pos);
-    json[pos] = '}';
+    json[pos++] = '}';
+    json[pos] = '\0';
     if(mqttConfig.payloadFormat == 5) {
         char topic[192];
         snprintf_P(topic, 192, PSTR("%s/list1"), mqttConfig.publishTopic);
@@ -127,7 +128,8 @@ bool JsonMqttHandler::publishList2(AmsData* data, EnergyAccounting* ea) {
         data->getL3Voltage()
     );
     pos += appendJsonFooter(ea, pos);
-    json[pos] = '}';
+    json[pos++] = '}';
+    json[pos] = '\0';
     if(mqttConfig.payloadFormat == 5) {
         char topic[192];
         snprintf_P(topic, 192, PSTR("%s/list2"), mqttConfig.publishTopic);
@@ -163,7 +165,8 @@ bool JsonMqttHandler::publishList3(AmsData* data, EnergyAccounting* ea) {
         data->getMeterTimestamp()
     );
     pos += appendJsonFooter(ea, pos);
-    json[pos] = '}';
+    json[pos++] = '}';
+    json[pos] = '\0';
     if(mqttConfig.payloadFormat == 5) {
         char topic[192];
         snprintf_P(topic, 192, PSTR("%s/list3"), mqttConfig.publishTopic);
@@ -215,7 +218,8 @@ bool JsonMqttHandler::publishList4(AmsData* data, EnergyAccounting* ea) {
         data->getMeterTimestamp()
     );
     pos += appendJsonFooter(ea, pos);
-    json[pos] = '}';
+    json[pos++] = '}';
+    json[pos] = '\0';
     if(mqttConfig.payloadFormat == 5) {
         char topic[192];
         snprintf_P(topic, 192, PSTR("%s/list4"), mqttConfig.publishTopic);
@@ -256,7 +260,8 @@ bool JsonMqttHandler::publishTemperatures(AmsConfiguration* config, HwTools* hw)
     bool ret = false;
     json[pos-1] = '}';
     if(mqttConfig.payloadFormat != 6) {
-        json[pos] = '}';
+        json[pos++] = '}';
+        json[pos] = '\0';
     }
     if(mqttConfig.payloadFormat == 5) {
         char topic[192];
@@ -382,7 +387,8 @@ bool JsonMqttHandler::publishPrices(PriceService* ps) {
         ts6hr
     );
     if(mqttConfig.payloadFormat != 6) {
-        json[pos] = '}';
+        json[pos++] = '}';
+        json[pos] = '\0';
     }
     bool ret = false;
     if(mqttConfig.payloadFormat == 5) {
diff --git a/lib/SvelteUi/src/AmsWebServer.cpp b/lib/SvelteUi/src/AmsWebServer.cpp
index cbc04657..7dfe4ba0 100644
--- a/lib/SvelteUi/src/AmsWebServer.cpp
+++ b/lib/SvelteUi/src/AmsWebServer.cpp
@@ -1181,6 +1181,7 @@ void AmsWebServer::handleSave() {
 				case 6: // Pow-P1
 					meterConfig.baud = 115200;
 					meterConfig.parity = 3; // 8N1
+					meterConfig.bufferSize = 8;
 					break;
 				case 3: // Pow-K UART0
 				case 5: // Pow-K+
@@ -1200,6 +1201,9 @@ void AmsWebServer::handleSave() {
 					network.sleep = 2; // Light sleep
 					break;
 			}
+			#if defined(ESP8266)
+				meterConfig.bufferSize = 1;
+			#endif
 			config->setNetworkConfig(network);
 			config->setMeterConfig(meterConfig);
 			
diff --git a/src/PassiveMeterCommunicator.cpp b/src/PassiveMeterCommunicator.cpp
index 9580db42..c472eb20 100644
--- a/src/PassiveMeterCommunicator.cpp
+++ b/src/PassiveMeterCommunicator.cpp
@@ -172,26 +172,6 @@ bool PassiveMeterCommunicator::loop() {
     dataAvailable = true;
 	lastError = DATA_PARSE_OK;
 
-	// After one hour, adjust buffer size to match the largest payload
-	if(!maxDetectPayloadDetectDone && now > 3600000) {
-		if(maxDetectedPayloadSize * 1.25 > meterConfig.bufferSize * 64) {
-			int bufferSize = min((double) 64, ceil((maxDetectedPayloadSize * 1.25) / 64));
-			#if defined(ESP8266)
-				if(meterConfig.rxPin != 3 && meterConfig.rxPin != 113) {
-					bufferSize = min(bufferSize, 2);
-				} else {
-					bufferSize = min(bufferSize, 8);
-				}
-			#endif
-			if(bufferSize != meterConfig.bufferSize) {
-				if (debugger->isActive(RemoteDebug::INFO)) debugger->printf_P(PSTR("Increasing RX buffer to %d bytes\n"), meterConfig.bufferSize * 64);
-				meterConfig.bufferSize = bufferSize;
-            	configChanged = true;
-			}
-		}
-		maxDetectPayloadDetectDone = true;
-	}
-
     return true;
 }
 
@@ -671,7 +651,7 @@ void PassiveMeterCommunicator::rxerr(int err) {
 		case 2:
 			if (debugger->isActive(RemoteDebug::ERROR)) debugger->printf_P(PSTR("Serial buffer overflow\n"));
 			rxBufferErrors++;
-			if(rxBufferErrors > 3 && meterConfig.bufferSize < 64) {
+			if(rxBufferErrors > 1 && meterConfig.bufferSize < 8) {
 				meterConfig.bufferSize += 2;
 				if (debugger->isActive(RemoteDebug::INFO)) debugger->printf_P(PSTR("Increasing RX buffer to %d bytes\n"), meterConfig.bufferSize * 64);
                 configChanged = true;