I tested it some weeks ago again after a year. The default upload from IDE should work, but mDNS in esp-link has now a bug and propagates the service only in AP mode so in STA mode the IDE doesn't show the network port.
from command line you can upload OTA with arduinoOTA tool used by IDE
example:
/home/duro/.arduino15/packages/arduino/tools/arduinoOTA/1.1.1/bin/arduinoOTA -address 192.168.1.104 -port 80 -sketch /tmp/arduino_build_89762/Blink.ino.hex -upload /pgm/upload -sync /pgm/sync -reset /log/reset -sync_exp 204:SYNC
If the mdns bug was fixed, for upload from IDE some settings must be addadded to board.txt
uno.upload.network.endpoint_upload=/pgm/upload
uno.upload.network.endpoint_sync=/pgm/sync
uno.upload.network.sync_return=204:SYNC
uno.upload.network.endpoint_reset=/log/reset
uno.upload.network.port=80
Uno WiFi uses an old version of esp-link so the settings and tutorial apply
