Arduino library to update the sketch over the network

This library allows you to update sketches on your board over WiFi or Ethernet.

The library is a modification of the Arduino WiFi101OTA library.

Contents

• Supported micro-controllers
• Supported networking libraries
• Installation
• OTA Upload from IDE without 'network port'
• OTA update as download
• ATmega support
• ESP8266 and ESP32 support
• nRF5 support
• Arduino 'network port'
• Troubleshooting
• Boards tested

Supported micro-controllers

• classic ATmega AVR with at least 64 kB of flash (Arduino Mega, MegaCore MCUs, MightyCore 1284p and 644)
• Arduino SAMD boards like Zero, M0, MKR and Nano 33 IoT
• Arduino Uno R4 boards
• nRF5 board supported by nRF5 core.
• RP2040 boards with Pico core
• STM32F boards with STM32 core
• boards supported by ESP8266 and ESP32 Arduino boards package
• any board with MCU with SD bootloader
• any board with custom Storage and boot-load solution for that storage
• Nano RP2040 Connect with mbed core with custom storage example and SFU library

Supported networking libraries

The ArduinoOTA library will work with any proper Arduino Ethernet or WiFi library. For Ethernet library add #define OTETHERNET before including the ArduinoOTA library. If you don't want a network port or the library doesn't support it, add #define NO_OTA_PORT before including the ArduinoOTA library. If you only want to use InternalStorage without the network upload from IDE, add #define NO_OTA_NETWORK before including the ArduinoOTA library.

Tested libraries are:

• Ethernet library - Ethernet shields and modules with Wiznet 5100, 5200 and 5500 chips
• WiFi101 - MKR 1000, Arduino WiFi101 shield and Adafruit WINC1500 WiFi shield or module
• WiFiNINA - MKR 1010, MKR 4000, Nano 33 IoT and any supported MCU with attached ESP32 as SPI network adapter with WiFiNINA firmware
• WiFiS3 library of Arduino Uno R4 WiFi
• WiFiEspAT - esp8266 or ESP32 as network adapter with AT firmware
• EthernetENC - shields and modules with ENC28j60 chip
• WiFi library of the Pico Core including its Ethernet network interfaces

EthernetENC and WiFiEspAT doesn't support UDP multicast for MDNS, so Arduino IDE will not show the network upload port.

Installation

The library is in Library Manager of the Arduino IDE.

Note for platformio users: Please, don't use this library with platformio. It was not tested with platformio and most of the documentation doesn't apply.

Arduino SAMD boards (Zero, M0, MKR, Nano 33 IoT) are supported 'out of the box'. Additionally to upload over the internal flash as temporary storage, upload over SD card and over MEM shield's flash is possible. For upload over SD card use the SDU library as shown in the WiFi101_SD_OTA or similar for upload over MKR MEM shield use the SFU library.

For Uno R4, RP2040, nRF5 and STM32 boards, platform.local.txt from extras folder has to be copied into boards package installation folder. For nRF5 details scroll down. For RP2040 the bundled ArduinoOTA library must be deleted.

For ESP8266 and ESP32 boards, platform.local.txt from extras folder has to be copied into boards package installation folder and the bundled ArduinoOTA library must be deleted. For details scroll down.

ATmega boards require to flash a modified Optiboot bootloader for flash write operations. Details are below.

For other MCU upload over SD card is possible if the MCU has SD bootloader which can bootload the update bin from SD card. See the ATmega-SD example. Some MCU can use a second stage SD bootloader linked to the sketch as a library similar to SAMD package's SDU library.

With InternalStorage the sketch binary size is limited to half of the available flash memory size. The available flash size may be reduced by the bootloader and EEPROM emulation space.

For upload the 'OTA programmer' technique can be configured.

The upload tool in IDE gas a timeout 10 seconds. For some sketch size, MCU or library it is too short. To set longer timeout, download newer version of the tool, replace the 1.3.0 arduinoOTA executable and in platform.local.txt add the -t option in seconds.

OTA Upload from IDE without 'network port'

Some networking libraries don't have the UDP.beginMulticast function and can't start a MDNS service to propagate the network port for Arduino IDE. And sometimes the MDNS port is not detected for the good libraries too. Arduino IDE doesn't yet allow to enter the IP address.

The workaround is to configure a fake programmer for Arduino OTA. You can use my_boards as starting point. For Arduino Mega it is the best option for all ArduinoOTA aspects, for other boards it gives you control about your custom settings. In your copy of my_boards in programmers.txt, configure the IP address and restart the IDE. Note: the esp boards packages can't be used as referenced packages in my_boards style.

If you don't want to use my_boards, the platform.local.txt files for avr and samd in extras folder in this library contain the configuration for arduinoOTA tool as programmer. Copy platform.local.txt next to platform.txt in the hardware package of your board. The programmers.txt file can't have a 'local' extension so you have to add your OTA 'programmer' configuration into the existing programmers.txt file. Then restart the IDE.

Example OTA 'programmer' configuration in programmers.txt:

arduinoOTA104.name=Arduino OTA (192.168.1.104)
arduinoOTA104.program.tool=arduinoOTA
arduinoOTA104.program.tool.default=arduinoOTA
arduinoOTA104.ip=192.168.1.104

In IDE select in Tools menu the "Arduino OTA (...)" programmer and use "Upload using programmer" from the Sketch menu in IDE.

Important! If you test OTA with the 'fake' programmer, close the Serial Monitor in IDE. With Serial Monitor open, IDE will reset the board after upload tool finishes. The board then doesn't finish to apply the update.

OTA update as download

Note: For Arduino MKR WiFi 1010 and Arduino Nano 33 IoT the SNU library and storage support in the nina firmware can be used for OTA update as download. See the SNU library example in the IDE Examples menu.

Note: Don't use this for esp8266 and esp32 Arduino. Use the ESP8266httpUpdate and the esp32 HTTPUpdate library for OTA update download for esp8266/esp32. Or use the Update object from esp8266 core of the Update library directly.

The WiFi101OTA and ArduinoOTA libraries were created for upload from IDE. But in some scenarios as for example deployed sleeping battery powered devices it is better to have the update available for download by the device.

In advanced section of examples you can find examples of sketch update over download from a http server. One example shows update over the InternalStorage object of the ArduinoOTA library. The example for update over SD card doesn't use this library at all.

The Blynk library uses this library in its Blynk.Edgent examples to store and apply user's updated sketch downloaded from the Blynk IoT cloud storage.

ATmega support

The sizes of networking library and the SD library allows the use of ArduinoOTA library only with ATmega MCUs with at least 64 kB flash memory.

Side note: There are other network upload options for here excluded ATmega328p: (Ariadne bootloader for Wiznet chips, WiFiLink firmware for the esp8266) or AvrDudeTelnet upload (Linux only).

For upload with ArduinoOTA library over InternalStorage, Optiboot bootloader with copy_flash_pages function is required. MegaCore and MightyCore by MCUDude before version 3 has Optiboot binaries with copy_flash_pages function ready to be burn to your ATmega.

The most common Arduino ATmega board with more than 64 kB of flash memory is Arduino Mega. To use it with ArduinoOTA library, you can't use it directly with the Arduino AVR package, because the package doesn't have the right fuse settings for Mega with Optiboot. You can download my boards definitions and use it to burn the modified Optiboot and to upload sketches to your Mega over USB and over network.

For SDStorage a 'SD bootloader' is required to load the uploaded file from the SD card. The SDStorage was tested with zevero/avr_boot. Note that the zevero/avr_boot doesn't support USB upload of sketch. The ATmega_SD example shows how to use this ArduinoOTA library with SD bootloader.

To use remote upload from IDE with SDStorage or InternalStorage, copy platform.local.txt from extras/avr folder, next to platform.txt in the boards package used (Arduino-avr or MCUdude packages).

The IDE upload tool is installed with Arduino AVR core package. At least version 1.2 of the arduinoOTA tool is required. For upload from command line without IDE see the command template in extras/avr/platform.local.txt.

ESP8266 and ESP32 support

This library allows to upload a sketch to esp8266 or esp32 over Ethernet with Ethernet or EthernetENC library.

*Both esp8266 and esp32 Arduino core now support wired network as additional network interface for their networking (ST