OTA with Wemos D1 works perfectly. But I need similar solution also for my Arduino Nano connected to ethernet. It is located where is no wi-fi coverage and is also hardly physically accessible to be able to update script over USB.
Is there a sollution to do it like with Updating OTA is amazing but with arduino nano and enc28j60 ?
I don’t think it is possible with Nano and enc28j60.
enc28j60 needs more than 10Kb of code to work, while bootloader (only bootloader can do Firmware Upgrade) must fit in 2 Kb.
i was JUST thinking for this the other day,
i have Mega 2650 + W5100 setup - is there hope for me?
Yes in this case, there might be some hope.
But the provided Ethernet bootloader is for the ATmega328P / W5100.
I couldn’t find it for Mega - so probably no easy way yet, unless you want to code your own bootloader 
But, in theory it can be done.
TY this was my conclusion last time i thought about it… i will patiently await progress…
at least i use the Mega as my main controller, it is easily accessible in a bedroom cupboard, not in my roof, basement, subfloor or out in the garden like my ESP colony!
take a look on moteino project