@Flacer 

Hi,

Have you already tried if a reset might help?

From the user's manual:

"Press and hold the Reset button for at least 5 seconds to reset the powerline extender
to factory default settings. When Reset is triggered properly, all LEDs will turn off and
start on again."

As far as I am aware these Powerline adapters have no built-in recovery mechanism to recover from a failed firmware update. 

By the way, what is the name of the firmware zip file you downloaded from TP-Link's website that lead to the failed update?

  @woozle 

I don't remember which firmware I used. It's a long time that has happened.

The adapter works only with ethernet.

The web browser interface doesn't exist anymore.

Only one old Powerline app shows that it is capable of wifi connections.

Searching on the forum, I discovered that the bin version of firmware is a linux partition only for web interface.

PIB files are related to mac address hardware information and they change to the region (US, EU, AU) and to version.

NVM is something related to the chip, and it can improve speed over the network if upgraded with a new version.

WPA8630 uses the QUALCOM7550 chip.