diff --git a/Getting_Started.md b/Getting_Started.md
index 4d35903c..d66aeca0 100644
--- a/Getting_Started.md
+++ b/Getting_Started.md
@@ -217,6 +217,14 @@ Once your Ahoy DTU is running, you can use the Over The Air (OTA) capabilities t
 
 ! ATTENTION: If you update from a very low version to the newest, please make sure to wipe all flash data!
 
+#### Flashing on Linux with `esptool.py` (ESP32)
+1. install [esptool.py](https://docs.espressif.com/projects/esptool/en/latest/esp32/) if you haven't already.
+2. download and extract the latest release bin-file from [ahoy_](https://github.com/grindylow/ahoy/releases)
+3. `cd ahoy_v<XXX> && cp *esp32.bin esp32.bin`
+4. Perhaps you need to replace `/dev/ttyUSB0` to match your acual device in the following command. Execute it afterwards: `esptool.py --port /dev/ttyUSB0 --chip esp32 --before default_reset --after hard_reset   write_flash --flash_mode dout --flash_freq 40m --flash_size detect   0x1000 bootloader.bin   0x8000 partitions.bin   0x10000 esp32.bin`
+5. Unplug and replug your device.
+6. Open a serial monitor (e.g. Putty) @ 115200 Baud. You should see some messages regarding wifi.
+
 ## Connect to your Ahoy DTU
 
 When everything is wired up and the firmware is flashed, it is time to connect to your Ahoy DTU.
diff --git a/User_Manual.md b/User_Manual.md
index 242a2809..a7be8f80 100644
--- a/User_Manual.md
+++ b/User_Manual.md
@@ -321,6 +321,19 @@ Send Power Limit:
 - A persistent limit is only needed if you want to throttle your inverter permanently or you can use it to set a start value on the battery, which is then always the switch-on limit when switching on, otherwise it would ramp up to 100% without regulation, which is continuous load is not healthy.
 - You can set a new limit in the turn-off state, which is then used for on (switching on again), otherwise the last limit from before the turn-off is used, but of course this only applies if DC voltage is applied the whole time.
 - If the DC voltage is missing for a few seconds, the microcontroller in the inverter goes off and forgets everything that was temporary/non-persistent in the RAM: YieldDay, error memory, non-persistent limit.
+### Update your AHOY-DTU Firmware
+To update your AHOY-DTU, you have to download the latest firmware package.
+Here are the [latest stable releases](https://github.com/lumapu/ahoy/releases/) and [latest development builds](https://nightly.link/lumapu/ahoy/workflows/compile_development/development03/ahoydtu_dev.zip) available for download.
+As soon as you have downloaded the firmware package, unzip it. On the WebUI, navigate to Update and press on select firmware file.
+From the unzipped files, select the right .bin file for your hardware and needs.
+- If you use an ESP8266, select the file ending with esp8266.bin 
+- If you use an ESP8266 with prometheus, select the file ending with esp8266_prometheus.bin 
+- If you use an ESP32, select the file ending with esp32.bin
+- If you use an ESP32 with prometheus, select the file ending with esp32_prometheus.bin
+
+Note: if you want to use prometheus, the usage of an ESP32 is recommended, since the ESP8266 is at its performance limits and therefore can cause stability issues.
+
+After selecting the right firmware file, press update. Your AHOY-DTU will now install the new firmware and reboot.
 
 ## Additional Notes
 ### MI Inverters
diff --git a/src/CHANGES.md b/src/CHANGES.md
index 9f83f7e7..94b1d10a 100644
--- a/src/CHANGES.md
+++ b/src/CHANGES.md
@@ -1,5 +1,8 @@
 # Development Changes
 
+## 0.6.13 - 2023-05-16
+* merge PR #934 (fix JSON API) and #944 (update manual)
+
 ## 0.6.12 - 2023-04-28
 * improved MqTT
 * fix menu active item
diff --git a/src/defines.h b/src/defines.h
index cf9395d5..22f5c8fb 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -13,7 +13,7 @@
 //-------------------------------------
 #define VERSION_MAJOR       0
 #define VERSION_MINOR       6
-#define VERSION_PATCH       12
+#define VERSION_PATCH       13
 
 //-------------------------------------
 typedef struct {
diff --git a/src/hm/hmRadio.h b/src/hm/hmRadio.h
index 7b8250fd..dba24bb3 100644
--- a/src/hm/hmRadio.h
+++ b/src/hm/hmRadio.h
@@ -84,8 +84,8 @@ class HmRadio {
             DTU_RADIO_ID = ((uint64_t)(((dtuSn >> 24) & 0xFF) | ((dtuSn >> 8) & 0xFF00) | ((dtuSn << 8) & 0xFF0000) | ((dtuSn << 24) & 0xFF000000)) << 8) | 0x01;
 
             #ifdef ESP32
-                #if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3
-                    mSpi = new SPIClass(FSPI);
+                #if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32S3
+                    mSpi = new SPIClass(HSPI);
                 #else
                     mSpi = new SPIClass(VSPI);
                 #endif
diff --git a/src/hms/esp32_3wSpi.h b/src/hms/esp32_3wSpi.h
index 0d494ba6..080e2251 100644
--- a/src/hms/esp32_3wSpi.h
+++ b/src/hms/esp32_3wSpi.h
@@ -11,12 +11,21 @@
 #include "driver/spi_master.h"
 #include "esp_rom_gpio.h" // for esp_rom_gpio_connect_out_signal
 
+#if CONFIG_IDF_TARGET_ESP32S3
+#define CLK_PIN     6
+#define MOSI_PIN    5
+#else
 #define CLK_PIN     18
 #define MOSI_PIN    23
-#define MISO_PIN    -1
+#endif
 
 #define SPI_CLK     1 * 1000 * 1000 // 1MHz
 
+#define SPI_PARAM_LOCK() \
+    do {                 \
+    } while (xSemaphoreTake(paramLock, portMAX_DELAY) != pdPASS)
+#define SPI_PARAM_UNLOCK() xSemaphoreGive(paramLock)
+
 // for ESP32 this is the so-called HSPI
 // for ESP32-S2/S3/C3 this nomenclature does not really exist anymore,
 // it is simply the first externally usable hardware SPI master controller
@@ -30,9 +39,10 @@ class esp32_3wSpi {
         }
 
         void setup(uint8_t pinCsb = CSB_PIN, uint8_t pinFcsb = FCSB_PIN) { //, uint8_t pinGpio3 = GPIO3_PIN) {
+            paramLock = xSemaphoreCreateMutex();
             spi_bus_config_t buscfg = {
                 .mosi_io_num = MOSI_PIN,
-                .miso_io_num = MISO_PIN,
+                .miso_io_num = -1, // single wire MOSI/MISO
                 .sclk_io_num = CLK_PIN,
                 .quadwp_io_num = -1,
                 .quadhd_io_num = -1,
@@ -93,7 +103,9 @@ class esp32_3wSpi {
                 .tx_buffer = &tx_data,
                 .rx_buffer = NULL
             };
+            SPI_PARAM_LOCK();
             ESP_ERROR_CHECK(spi_device_polling_transmit(spi_reg, &t));
+            SPI_PARAM_UNLOCK();
             delayMicroseconds(100);
         }
 
@@ -110,7 +122,10 @@ class esp32_3wSpi {
                 .tx_buffer = NULL,
                 .rx_buffer = &rx_data
             };
+
+            SPI_PARAM_LOCK();
             ESP_ERROR_CHECK(spi_device_polling_transmit(spi_reg, &t));
+            SPI_PARAM_UNLOCK();
             delayMicroseconds(100);
             return rx_data;
         }
@@ -126,11 +141,13 @@ class esp32_3wSpi {
                 .rx_buffer = NULL
             };
 
+            SPI_PARAM_LOCK();
             for(uint8_t i = 0; i < len; i++) {
                 tx_data = ~buf[i]; // negate buffer contents
                 ESP_ERROR_CHECK(spi_device_polling_transmit(spi_fifo, &t));
                 delayMicroseconds(4); // > 4 us
             }
+            SPI_PARAM_UNLOCK();
         }
 
         void readFifo(uint8_t buf[], uint8_t len) {
@@ -145,16 +162,19 @@ class esp32_3wSpi {
                 .rx_buffer = &rx_data
             };
 
+        SPI_PARAM_LOCK();
             for(uint8_t i = 0; i < len; i++) {
                 ESP_ERROR_CHECK(spi_device_polling_transmit(spi_fifo, &t));
                 delayMicroseconds(4); // > 4 us
                 buf[i] = rx_data;
             }
+        SPI_PARAM_UNLOCK();
         }
 
     private:
         spi_device_handle_t spi_reg, spi_fifo;
         bool mInitialized;
+        SemaphoreHandle_t paramLock = NULL;
 };
 #else
     template<uint8_t CSB_PIN=5, uint8_t FCSB_PIN=4>
diff --git a/src/web/RestApi.h b/src/web/RestApi.h
index 4d5c3a85..ea08f8c0 100644
--- a/src/web/RestApi.h
+++ b/src/web/RestApi.h
@@ -563,7 +563,7 @@ class RestApi {
 
             if(F("power") == jsonIn[F("cmd")])
                 accepted = iv->setDevControlRequest((jsonIn[F("val")] == 1) ? TurnOn : TurnOff);
-            else if(F("restart") == jsonIn[F("restart")])
+            else if(F("restart") == jsonIn[F("cmd")])
                 accepted = iv->setDevControlRequest(Restart);
             else if(0 == strncmp("limit_", jsonIn[F("cmd")].as<const char*>(), 6)) {
                 iv->powerLimit[0] = jsonIn["val"];
diff --git a/tools/rpi/ahoy.yml.example b/tools/rpi/ahoy.yml.example
index 9301067f..00d52511 100644
--- a/tools/rpi/ahoy.yml.example
+++ b/tools/rpi/ahoy.yml.example
@@ -2,11 +2,14 @@
 
 ahoy:
   interval: 5
+  transmit_retries: 5
 
   logging:
     filename: 'hoymiles.log'
     # DEBUG, INFO, WARNING, ERROR, FATAL
     level: 'INFO'
+    max_log_filesize: 1000000
+    max_log_files: 1
 
   sunset:
     disabled: false
diff --git a/tools/rpi/hoymiles/__init__.py b/tools/rpi/hoymiles/__init__.py
index 210bed65..688e271d 100644
--- a/tools/rpi/hoymiles/__init__.py
+++ b/tools/rpi/hoymiles/__init__.py
@@ -297,8 +297,8 @@ class InverterPacketFragment:
 
 class HoymilesNRF:
     """Hoymiles NRF24 Interface"""
-    tx_channel_id = 0
-    tx_channel_list = [40]
+    tx_channel_id = 2
+    tx_channel_list = [3,23,40,61,75]
     rx_channel_id = 0
     rx_channel_list = [3,23,40,61,75]
     rx_channel_ack = False
@@ -332,6 +332,12 @@ class HoymilesNRF:
         :rtype: bool
         """
 
+        self.next_tx_channel()
+
+        if HOYMILES_TRANSACTION_LOGGING:
+            c_datetime = datetime.now().strftime("%Y-%m-%d %H:%M:%S.%f")
+            logging.debug(f'{c_datetime} Transmit {len(packet)} bytes channel {self.tx_channel}: {hexify_payload(packet)}')
+
         if not txpower:
             txpower = self.txpower
 
@@ -363,13 +369,13 @@ class HoymilesNRF:
         """
         Receive Packets
 
-        :param timeout: receive timeout in nanoseconds (default: 12e8)
+        :param timeout: receive timeout in nanoseconds (default: 5e8)
         :type timeout: int
         :yields: fragment
         """
 
         if not timeout:
-            timeout=12e8
+            timeout=5e8
 
         self.radio.setChannel(self.rx_channel)
         self.radio.setAutoAck(False)
@@ -415,7 +421,7 @@ class HoymilesNRF:
                     self.radio.setChannel(self.rx_channel)
                     self.radio.startListening()
 
-            time.sleep(0.005)
+            time.sleep(0.004)
 
     def next_rx_channel(self):
         """
@@ -433,6 +439,15 @@ class HoymilesNRF:
             return True
         return False
 
+    def next_tx_channel(self):
+        """
+        Select next channel from hop list
+
+        """
+        self.tx_channel_id = self.tx_channel_id + 1
+        if self.tx_channel_id >= len(self.tx_channel_list):
+            self.tx_channel_id = 0
+
     @property
     def tx_channel(self):
         """
@@ -612,10 +627,6 @@ class InverterTransaction:
 
         packet = self.tx_queue.pop(0)
 
-        if HOYMILES_TRANSACTION_LOGGING:
-            c_datetime = datetime.now().strftime("%Y-%m-%d %H:%M:%S.%f")
-            logging.debug(f'{c_datetime} Transmit {len(packet)} | {hexify_payload(packet)}')
-
         self.radio.transmit(packet, txpower=self.txpower)
 
         wait = False
diff --git a/tools/rpi/hoymiles/__main__.py b/tools/rpi/hoymiles/__main__.py
index 7de4a1a2..3589de1a 100644
--- a/tools/rpi/hoymiles/__main__.py
+++ b/tools/rpi/hoymiles/__main__.py
@@ -19,6 +19,7 @@ import yaml
 from yaml.loader import SafeLoader
 import hoymiles
 import logging
+from logging.handlers import RotatingFileHandler
 
 ################################################################################
 """ Signal Handler """
@@ -127,6 +128,7 @@ def main_loop(ahoy_config):
     dtu_name = ahoy_config.get('dtu', {}).get('name', 'hoymiles-dtu')
     sunset.sun_status2mqtt(dtu_ser, dtu_name)
     loop_interval = ahoy_config.get('interval', 1)
+    transmit_retries = ahoy_config.get('transmit_retries', 5)
 
     try:
         do_init = True
@@ -143,7 +145,7 @@ def main_loop(ahoy_config):
                    sys.exit(999)
                 if hoymiles.HOYMILES_DEBUG_LOGGING:
                     logging.info(f'Poll inverter name={inverter["name"]} ser={inverter["serial"]}')
-                poll_inverter(inverter, dtu_ser, do_init, 3)
+                poll_inverter(inverter, dtu_ser, do_init, transmit_retries)
             do_init = False
 
             if loop_interval > 0:
@@ -298,6 +300,8 @@ def init_logging(ahoy_config):
     log_config = ahoy_config.get('logging')
     fn = 'hoymiles.log'
     lvl = logging.ERROR
+    max_log_filesize = 1000000
+    max_log_files = 1
     if log_config:
         fn = log_config.get('filename', fn)
         level = log_config.get('level', 'ERROR')
@@ -311,9 +315,11 @@ def init_logging(ahoy_config):
             lvl = logging.ERROR
         elif level == 'FATAL':
             lvl = logging.FATAL
+        max_log_filesize  = log_config.get('max_log_filesize', max_log_filesize)
+        max_log_files = log_config.get('max_log_files', max_log_files)
     if hoymiles.HOYMILES_TRANSACTION_LOGGING:
        lvl = logging.DEBUG
-    logging.basicConfig(filename=fn, format='%(asctime)s %(levelname)s: %(message)s', datefmt='%Y-%m-%d %H:%M:%S', level=lvl)
+    logging.basicConfig(handlers=[RotatingFileHandler(fn, maxBytes=max_log_filesize, backupCount=max_log_files)], format='%(asctime)s %(levelname)s: %(message)s', datefmt='%Y-%m-%d %H:%M:%S', level=lvl)
     dtu_name = ahoy_config.get('dtu',{}).get('name','hoymiles-dtu')
     logging.info(f'start logging for {dtu_name} with level: {logging.root.level}')
 
diff --git a/tools/rpi/hoymiles/decoders/__init__.py b/tools/rpi/hoymiles/decoders/__init__.py
index bb32fb07..ad49d664 100644
--- a/tools/rpi/hoymiles/decoders/__init__.py
+++ b/tools/rpi/hoymiles/decoders/__init__.py
@@ -515,9 +515,17 @@ class Hm300Decode0B(StatusResponse):
         """ reactive power """
         return self.unpack('>H', 20)[0]/10
     @property
+    def powerfactor(self):
+        """ Powerfactor """
+        return self.unpack('>H', 24)[0]/1000
+    @property
     def temperature(self):
         """ Inverter temperature in °C """
         return self.unpack('>h', 26)[0]/10
+    @property
+    def event_count(self):
+        """ Event counter """
+        return self.unpack('>H', 28)[0]
 
 class Hm300Decode0C(Hm300Decode0B):
     """ 1121-series mirco-inverters status data """