I have a 50NANO79SNA, built in 2020. After ignoring the message for some time I finally decided to allow it to do an automatic firmware update. Started the process then went to bed.
In the morning the TV appeared to have hung up - it was turned on but had no picture, no audio and did not respond to the remote. I turned the TV off using the manual power button then powered it back on... I got the LG power-on sound, but again no picture. Powering it off then back on again resulted in no sound, no picture and a power light that flashes 3 times each time it turns on. It does respond to the remote (for power on/off commands.)
Is there a way to force-reload the firmware over USB if you don't have a picture?