WiFi OTA Firmware

• Fits into 640KB for all esp32 targets
• Compatible with espota.py from arduino-esp32

Usage

Build and write OTA binary to the ota_1 partition (take its address from partition-table.csv):

pio run [-e <target>]
esptool.py --port <...> write_flash 0x260000 .pio/build/<target>/firmware.bin

After rebooting the device into OTA firmware (the main firmware has to have some way of doing that), upload a new main firmware binary over network:

espota.py --ip <device-ip-address> --file <new-main-firmware.bin>

Uploading a filesystem image to a spiffs partition:

espota.py --ip <device-ip-address> --file <littlefs.bin> --spiffs

Details

• To be able to connect to a WiFi access point, OTA firmware expects to find ssid and psk string fields in the NVRAM storage under ota-wifi namespace.
• After successful flashing, a boolean field updated is raised, so that the main firmware can handle the "first boot after update" scenario.
• OTA firmware waits for an upload only for some limited time and then reboots back to main on timeout.