diff --git a/README.md b/README.md
index 3ea97b9..ac6003d 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@
     - count the turns between these positions and set the trimmer in the middle position with D1 blinking
     - if you have adjusted the trimmer, disconnect and connect the adapter to bus again
 - search for WiFi networks, you should see network with name "esp-eBus"
-- connect to the network - a configuration page should open automatically
+- connect to the network - a configuration page should open automatically, default password is: ebusebus
 - configure your WiFi network settings (SSID, password)
 - after reboot, you should be able to run `ping esp-ebus.local` successfully from a computer in your network (if your network is correctly configured for mDNS)
 - to verify there are bytes being received by the adapter, you can connect to `esp-ebus.local` port `3334` using telnet - you should see unreadable binary data
@@ -138,15 +138,15 @@ There are following options:
     - heavier option - it will compile the firmware from source code and upload using internall tooling
   - [using espota.py](#espotapy)
     - lightweight - just needs OTA script and precompiled firmware file
-- physically using a USB-TTL adaptor
+- physically using a USB-TTL adaptor or device USB port (HW v5.0+)
 
 ### web interface
-- [reset device](#config-reset) to access config portal
-- connect to the esp-eBus WiFi network
-- click blue `Update` button
+- open web interface of the device by IP or on: http://esp-ebus.local
+- find the update link
 - upload correct firmware file (see hardware revisions)
-- click red `Update` button
-- wait for restart, reconnect to adapter and configure WiFi
+- click `Update` button
+- wait for restart, reconnect to adapter and configure WiFi if not connected automatically
+- in case you cannot open web interface, [reset device](#config-reset) to access it
 
 ### platform.io
 - clone this repository using git
@@ -179,7 +179,19 @@ Uploading: [============================================================] 100% D
 16:33:31 [INFO]: Result: OK
 ```
 
-### upgrading using USB-TTL adaptor
+### upgrading over USB (HW v5.0+)
+ - this version has built-in USB serial interface
+ - download `firmware-fullflash-*` firmware from https://github.com/danielkucera/esp8266-arduino-ebus/releases
+ - connect `PROG` and `GND`
+ - connect adapter to a PC using USB-A - USB-C cable
+ - you should see a new serial port
+ - flash the firmware to address 0x0 using either one of tools:
+   - Web based: https://adafruit.github.io/Adafruit_WebSerial_ESPTool/
+   - Windows: using Flash Download Tools from https://www.espressif.com/en/support/download/other-tools
+   - Linux esptool.py: `esptool.py write_flash 0x0 firmware-fullflash-*`
+
+
+### upgrading over USB-TTL adaptor (before HW v5.0)
 You will need an USB-TTL adaptor (dongle) which suports 3V3 voltage levels and has 3V3 voltage output pin
 - download firmware bin file from https://github.com/danielkucera/esp8266-arduino-ebus/releases
 - download NodeMCU PyFlasher from https://github.com/marcelstoer/nodemcu-pyflasher/releases
diff --git a/fullflash.sh b/fullflash.sh
index 24c740a..dd0ce1b 100755
--- a/fullflash.sh
+++ b/fullflash.sh
@@ -2,8 +2,9 @@
 
 OF=firmware-fullflash-HW_v5.x.bin 
 
-dd if=.pio/build/esp32-c3/bootloader.bin of=$OF
-dd if=.pio/build/esp32-c3/partitions.bin of=$OF bs=1 seek=$((0x8000))
-dd if=$HOME/.platformio/packages/framework-arduinoespressif32/tools/partitions/boot_app0.bin of=$OF bs=1 seek=$((0xe000))
+tr '\0' '\377' < /dev/zero | dd bs=1 count=$((0x10000)) of=$OF
+dd if=.pio/build/esp32-c3/bootloader.bin of=$OF conv=notrunc
+dd if=.pio/build/esp32-c3/partitions.bin of=$OF bs=1 seek=$((0x8000)) conv=notrunc
+dd if=$HOME/.platformio/packages/framework-arduinoespressif32/tools/partitions/boot_app0.bin of=$OF bs=1 seek=$((0xe000)) conv=notrunc
 dd if=.pio/build/esp32-c3/firmware.bin of=$OF bs=1 seek=$((0x10000))
 
diff --git a/platformio.ini b/platformio.ini
index 52921d9..519fb8d 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -11,9 +11,10 @@
 [env]
 framework = arduino
 lib_deps =
-    https://github.com/tzapu/WiFiManager#v2.0.14-beta
+    https://github.com/prampec/IotWebConf#v3.2.1
 extra_scripts =
     pre:auto_firmware_version.py
+monitor_filters = esp32_exception_decoder
 
 [env:esp12e]
 platform = espressif8266
@@ -23,8 +24,11 @@ upload_speed = 921600
 build_flags =
     -DRESET_PIN=5
     -DTX_DISABLE_PIN=5
+    -DBusSer=Serial
+    -DDebugSer=Serial1
+
 lib_deps =
-    https://github.com/tzapu/WiFiManager#v2.0.14-beta
+    ${env.lib_deps}
     https://github.com/marvinroger/ESP8266TrueRandom
     vshymanskyy/Preferences@^2.1.0
 
@@ -38,6 +42,8 @@ extends = env:esp12e
 build_flags =
     -DRESET_PIN=5
     -DTX_DISABLE_PIN=2
+    -DBusSer=Serial
+    -DDebugSer=Serial1
 
 [env:esp12e-v3-ota]
 extends = env:esp12e-v3
@@ -45,14 +51,21 @@ upload_port = esp-ebus.local
 upload_protocol = espota
 
 [env:esp32-c3]
-platform = espressif32
+platform = espressif32@6.5.0
 board = esp32-c3-devkitm-1
 build_flags =
     -DRESET_PIN=20
     -DPWM_PIN=6
+    -DARDUINO_USB_MODE=1
+    -DARDUINO_USB_CDC_ON_BOOT=1
+    -DBusSer=Serial1
+    -DDebugSer=Serial
+    -DSTATUS_LED_PIN=3
+
+monitor_filters = esp32_exception_decoder
 
 lib_deps =
-    https://github.com/tzapu/WiFiManager#v2.0.14-beta
+    ${env.lib_deps}
     https://github.com/guido4096/espsoftwareserial.git#add-startbit-timestamp
 
 [env:esp32-c3-ota]
diff --git a/src/arbitration.cpp b/src/arbitration.cpp
index a37b9e5..82a7397 100644
--- a/src/arbitration.cpp
+++ b/src/arbitration.cpp
@@ -27,7 +27,7 @@ Arbitration::result Arbitration::start(BusState& busstate, uint8_t master, unsig
     if (timeSinceStartBit > 4456 || Bus.available()) 
     {
         // if we are too late, don't try to participate and retry next round
-        DEBUG_LOG("ARB LATE 0x%02x %lu us\n", Serial.peek(), timeSinceStartBit);
+        DEBUG_LOG("ARB LATE 0x%02x %lu us\n", BusSer.peek(), timeSinceStartBit);
         return late;
     }
 #if USE_ASYNCHRONOUS
diff --git a/src/bus.cpp b/src/bus.cpp
index 0fc4b0e..9ffa3f3 100644
--- a/src/bus.cpp
+++ b/src/bus.cpp
@@ -119,21 +119,21 @@ void BusType::begin() {
 
 #if USE_SOFTWARE_SERIAL
  #if defined(ESP32)
-  Serial.begin(2400, SERIAL_8N1, -1, UART_TX); // used for writing
+  BusSer.begin(2400, SERIAL_8N1, -1, UART_TX); // used for writing
  #elif defined(ESP8266)
-  Serial.begin(2400, SERIAL_8N1, SERIAL_TX_ONLY, UART_TX);
+  BusSer.begin(2400, SERIAL_8N1, SERIAL_TX_ONLY, UART_TX);
  #endif
   mySerial.enableStartBitTimeStampRecording(true);
   mySerial.enableTx(false);
   mySerial.enableIntTx(false);
   mySerial.begin(2400, SWSERIAL_8N1, UART_RX, -1, false, RXBUFFERSIZE); // used for reading
 #else
-  Serial.setRxBufferSize(RXBUFFERSIZE);
+  BusSer.setRxBufferSize(RXBUFFERSIZE);
  #if defined(ESP32)
-  Serial.begin(2400, SERIAL_8N1, UART_RX, UART_TX); // used for writing
-  Serial.setRxFIFOFull(1);
+  BusSer.begin(2400, SERIAL_8N1, UART_RX, UART_TX); // used for writing
+  BusSer.setRxFIFOFull(1);
  #elif defined(ESP8266)
-  Serial.begin(2400);
+  BusSer.begin(2400);
  #endif
 #endif
 
@@ -145,7 +145,7 @@ void BusType::begin() {
 }
 
 void BusType::end() {
-  Serial.end();
+  BusSer.end();
 #if USE_SOFTWARE_SERIAL
   mySerial.end();
 #endif
@@ -161,11 +161,11 @@ void BusType::end() {
 
 
 int BusType::availableForWrite() {
-  return Serial.availableForWrite();
+  return BusSer.availableForWrite();
 }
 
 size_t BusType::write(uint8_t symbol) {
-  return Serial.write(symbol);
+  return BusSer.write(symbol);
 }
 
 bool BusType::read(data& d) {
@@ -178,8 +178,8 @@ bool BusType::read(data& d) {
         receive(symbol, mySerial.readStartBitTimeStamp());
     }
   #else
-    if (Serial.available()){
-        uint8_t symbol = Serial.read();
+    if (BusSer.available()){
+        uint8_t symbol = BusSer.read();
         receive(symbol, micros());
     }
   #endif
@@ -196,7 +196,7 @@ int BusType::available() {
 #if USE_SOFTWARE_SERIAL
   return mySerial.available(); 
 #else
-  return Serial.available();
+  return BusSer.available();
 #endif  
 }
 
diff --git a/src/client.cpp b/src/client.cpp
index b4cc8af..cc49ccf 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -9,7 +9,7 @@ bool handleNewClient(WiFiServer &server, WiFiClient clients[]) {
   int i;
   for (i = 0; i < MAX_SRV_CLIENTS; i++) {
     if (!clients[i]) { // equivalent to !serverClients[i].connected()
-      clients[i] = server.available();
+      clients[i] = server.accept();
       clients[i].setNoDelay(true);
       break;
     }
@@ -17,7 +17,7 @@ bool handleNewClient(WiFiServer &server, WiFiClient clients[]) {
 
   // No free/disconnected slot so reject
   if (i == MAX_SRV_CLIENTS) {
-    server.available().println("busy");
+    server.accept().println("busy");
     // hints: server.available() is a WiFiClient with short-term scope
     // when out of scope, a WiFiClient will
     // - flush() - all data will be sent
diff --git a/src/main.cpp b/src/main.cpp
index 052d03d..8daaf3c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,6 @@
 #include <ArduinoOTA.h>
-#include <WiFiManager.h>          //https://github.com/tzapu/WiFiManager WiFi Configuration Magic
+#include <IotWebConf.h>
+#include <IotWebConfUsing.h>
 #include "main.hpp"
 #include "enhanced.hpp"
 #include "bus.hpp"
@@ -11,9 +12,15 @@ Preferences preferences;
   #include <esp_task_wdt.h>
   #include <ESPmDNS.h>
   #include "esp32c3/rom/rtc.h"
+  #include <IotWebConfESP32HTTPUpdateServer.h>
+
+  HTTPUpdateServer httpUpdater;
 #else
   #include <ESP8266mDNS.h>
   #include <ESP8266TrueRandom.h>
+  #include <ESP8266HTTPUpdateServer.h>
+
+  ESP8266HTTPUpdateServer httpUpdater;
 #endif
 
 #define ALPHA 0.3
@@ -24,13 +31,18 @@ Preferences preferences;
 
 #define DEFAULT_AP "ebus-test"
 #define DEFAULT_PASS "lectronz"
+#define DEFAULT_APMODE_PASS "ebusebus"
 
 #ifdef ESP32
 TaskHandle_t Task1;
 #endif
 
-WiFiManager wifiManager(Serial1);
-WiFiManagerParameter param_pwm_value("pwm_value", "PWM value", "", 6);
+#define CONFIG_VERSION "eea"
+DNSServer dnsServer;
+WebServer configServer(80);
+char pwm_value_string[8];
+IotWebConf iotWebConf(HOSTNAME, &dnsServer, &configServer, "", CONFIG_VERSION);
+IotWebConfNumberParameter pwm_value_param = IotWebConfNumberParameter("PWM value", "pwm_value", pwm_value_string, 8, "130", "1..255", "min='1' max='255' step='1'");
 
 WiFiServer wifiServer(3333);
 WiFiServer wifiServerRO(3334);
@@ -50,7 +62,7 @@ int reconnectCount = 0;
 
 int random_ch(){
 #ifdef ESP32
-  return 6;
+  return esp_random() % 13 + 1 ;
 #elif defined(ESP8266)
   return ESP8266TrueRandom.random(1, 13);
 #endif
@@ -185,13 +197,75 @@ void data_loop(void * pvParameters){
   }
 }
 
+
 void saveParamsCallback () {
-  uint8_t new_pwm_value = atoi(param_pwm_value.getValue());
+
+  uint8_t new_pwm_value = atoi(pwm_value_string);
   if (new_pwm_value > 0){
     set_pwm(new_pwm_value);
     preferences.putUInt("pwm_value", new_pwm_value);
   }
-  Serial1.printf("pwm_value set: %s %d\n", param_pwm_value.getValue(), new_pwm_value);
+  DebugSer.printf("pwm_value set: %s %d\n", pwm_value_string, new_pwm_value);
+
+}
+
+char* status_string(){
+  static char status[1024];
+
+  int pos = 0;
+
+  pos += sprintf(status + pos, "async mode: %s\n", USE_ASYNCHRONOUS ? "true" : "false");
+  pos += sprintf(status + pos, "software serial mode: %s\n", USE_SOFTWARE_SERIAL ? "true" : "false");
+  pos += sprintf(status + pos, "uptime: %ld ms\n", millis());
+  pos += sprintf(status + pos, "last_connect_time: %ld ms\n", lastConnectTime);
+  pos += sprintf(status + pos, "reconnect_count: %d \n", reconnectCount);
+  pos += sprintf(status + pos, "rssi: %d dBm\n", WiFi.RSSI());
+  pos += sprintf(status + pos, "free_heap: %d B\n", ESP.getFreeHeap());
+  pos += sprintf(status + pos, "reset_code: %d\n", last_reset_code);
+  pos += sprintf(status + pos, "loop_duration: %ld us\r\n", loopDuration);
+  pos += sprintf(status + pos, "max_loop_duration: %ld us\r\n", maxLoopDuration);
+  pos += sprintf(status + pos, "version: %s\r\n", AUTO_VERSION);
+  pos += sprintf(status + pos, "nbr arbitrations: %i\r\n", (int)Bus._nbrArbitrations);
+  pos += sprintf(status + pos, "nbr restarts1: %i\r\n", (int)Bus._nbrRestarts1);
+  pos += sprintf(status + pos, "nbr restarts2: %i\r\n", (int)Bus._nbrRestarts2);
+  pos += sprintf(status + pos, "nbr lost1: %i\r\n", (int)Bus._nbrLost1);
+  pos += sprintf(status + pos, "nbr lost2: %i\r\n", (int)Bus._nbrLost2);
+  pos += sprintf(status + pos, "nbr won1: %i\r\n", (int)Bus._nbrWon1);
+  pos += sprintf(status + pos, "nbr won2: %i\r\n", (int)Bus._nbrWon2);
+  pos += sprintf(status + pos, "nbr late: %i\r\n", (int)Bus._nbrLate);
+  pos += sprintf(status + pos, "nbr errors: %i\r\n", (int)Bus._nbrErrors);
+  pos += sprintf(status + pos, "pwm_value: %i\r\n", get_pwm());
+
+  return status;
+}
+
+void handleStatus()
+{
+  configServer.send(200, "text/plain", status_string());
+}
+
+
+void handleRoot()
+{
+  // -- Let IotWebConf test and handle captive portal requests.
+  if (iotWebConf.handleCaptivePortal())
+  {
+    // -- Captive portal request were already served.
+    return;
+  }
+  String s = "<html><head><title>esp-eBus adapter</title>";
+  s += "<meta name=\"viewport\" content=\"width=device-width, initial-scale=1, user-scalable=no\"/>";
+  s += "</head><body>";
+  s += "<a href='/status'>Adapter status</a><br>";
+  s += "<a href='/config'>Configuration</a> - user: admin password: your configured AP mode password or default: ";
+  s += DEFAULT_APMODE_PASS;
+  s += "<br>";
+  s += "<a href='/firmware'>Firmware update</a><br>";
+  s += "<br>";
+  s += "For more info see project page: <a href='https://github.com/danielkucera/esp-arduino-ebus'>https://github.com/danielkucera/esp-arduino-ebus</a>";
+  s += "</body></html>";
+
+  configServer.send(200, "text/html", s);
 }
 
 void setup() {
@@ -200,15 +274,14 @@ void setup() {
   check_reset();
 
 #ifdef ESP32
-  Serial1.begin(115200, SERIAL_8N1, 10, 9);
   last_reset_code = rtc_get_reset_reason(0);
 #elif defined(ESP8266)
-  Serial1.begin(115200);
   last_reset_code = (int) ESP.getResetInfoPtr();
 #endif
   Bus.begin();
 
-  Serial1.setDebugOutput(true);
+  DebugSer.begin(115200);
+  DebugSer.setDebugOutput(true);
 
   disableTX();
 
@@ -221,24 +294,49 @@ void setup() {
 
   if (preferences.getBool("firstboot", true)){
     preferences.putBool("firstboot", false);
-    WiFi.begin(DEFAULT_AP, DEFAULT_PASS);
+    iotWebConf.init();
+    strncpy(iotWebConf.getApPasswordParameter()->valueBuffer, DEFAULT_APMODE_PASS, IOTWEBCONF_WORD_LEN);
+    strncpy(iotWebConf.getWifiSsidParameter()->valueBuffer, "ebus-test", IOTWEBCONF_WORD_LEN);
+    strncpy(iotWebConf.getWifiPasswordParameter()->valueBuffer, "lectronz", IOTWEBCONF_WORD_LEN);
+    iotWebConf.saveConfig();
+  } else {
+    iotWebConf.skipApStartup();
   }
 
-  WiFi.enableAP(false);
-  WiFi.begin();
-
 #ifdef ESP32
   WiFi.onEvent(on_connected, WiFiEvent_t::ARDUINO_EVENT_WIFI_STA_CONNECTED);
 #endif
 
-  wifiManager.setSaveParamsCallback(saveParamsCallback);
-  wifiManager.addParameter(&param_pwm_value);
+  int wifi_ch = random_ch();
+  DebugSer.printf("Channel for AP mode: %d\n", wifi_ch);
+  WiFi.channel(wifi_ch); // doesn't work, https://github.com/prampec/IotWebConf/issues/286
+
+  iotWebConf.addSystemParameter(&pwm_value_param);
+  iotWebConf.setConfigSavedCallback(&saveParamsCallback);
+  iotWebConf.getApTimeoutParameter()->visible = true;
+  iotWebConf.setWifiConnectionTimeoutMs(7000);
+
+#ifdef STATUS_LED_PIN
+  iotWebConf.setStatusPin(STATUS_LED_PIN);
+#endif
 
-  wifiManager.setHostname(HOSTNAME);
-  wifiManager.setConfigPortalTimeout(120);
-  wifiManager.setWiFiAPChannel(random_ch());
-  wifiManager.autoConnect(HOSTNAME);
-  wifiManager.startWebPortal();
+  // -- Initializing the configuration.
+  iotWebConf.init();
+
+  // -- Set up required URL handlers on the web server.
+  configServer.on("/", []{ handleRoot(); });
+  configServer.on("/config", []{ iotWebConf.handleConfig(); });
+  configServer.on("/param", []{ iotWebConf.handleConfig(); });
+  configServer.on("/status", []{ handleStatus(); });
+  configServer.onNotFound([](){ iotWebConf.handleNotFound(); });
+
+  iotWebConf.setupUpdateServer(
+    [](const char* updatePath) { httpUpdater.setup(&configServer, updatePath); },
+    [](const char* userName, char* password) { httpUpdater.updateCredentials(userName, password); });
+
+  while (iotWebConf.getState() != iotwebconf::NetworkState::OnLine){
+      iotWebConf.doLoop();
+  }
 
   wifiServer.begin();
   wifiServerRO.begin();
@@ -267,31 +365,10 @@ bool handleStatusServerRequests() {
   if (!statusServer.hasClient())
     return false;
 
-  WiFiClient client = statusServer.available();
+  WiFiClient client = statusServer.accept();
 
   if (client.availableForWrite() >= AVAILABLE_THRESHOLD) {
-    client.printf("async mode: %s\n", USE_ASYNCHRONOUS ? "true" : "false");
-    client.printf("software serial mode: %s\n", USE_SOFTWARE_SERIAL ? "true" : "false");
-    client.printf("uptime: %ld ms\n", millis());
-    client.printf("last_connect_time: %ld ms\n", lastConnectTime);
-    client.printf("reconnect_count: %d \n", reconnectCount);
-    client.printf("rssi: %d dBm\n", WiFi.RSSI());
-    client.printf("free_heap: %d B\n", ESP.getFreeHeap());
-    client.printf("reset_code: %d\n", last_reset_code);
-    client.printf("loop_duration: %ld us\r\n", loopDuration);
-    client.printf("max_loop_duration: %ld us\r\n", maxLoopDuration);
-    client.printf("version: %s\r\n", AUTO_VERSION);
-    client.printf("nbr arbitrations: %i\r\n", (int)Bus._nbrArbitrations);
-    client.printf("nbr restarts1: %i\r\n", (int)Bus._nbrRestarts1);
-    client.printf("nbr restarts2: %i\r\n", (int)Bus._nbrRestarts2);
-    client.printf("nbr lost1: %i\r\n", (int)Bus._nbrLost1);
-    client.printf("nbr lost2: %i\r\n", (int)Bus._nbrLost2);
-    client.printf("nbr won1: %i\r\n", (int)Bus._nbrWon1);
-    client.printf("nbr won2: %i\r\n", (int)Bus._nbrWon2);
-    client.printf("nbr late: %i\r\n", (int)Bus._nbrLate);
-    client.printf("nbr errors: %i\r\n", (int)Bus._nbrErrors);
-    client.printf("pwm_value: %i\r\n", get_pwm());
-
+    client.print(status_string());
     client.flush();
     client.stop();
   }
@@ -310,7 +387,7 @@ void loop() {
   wdt_feed();
 
 #ifdef ESP32
-  wifiManager.process();
+  iotWebConf.doLoop();
 #endif
 
   if (WiFi.status() != WL_CONNECTED) {