Hi, i have that router, which became bricked on a firmware update.
Tried the usual resets and loading firmware with ethernet cable but no connection at all , no ping or whatsoever.
All lights flashing all the time in the same sequence, the ethernet connection shows connected for a brief second before recconnect again every 5 second or so, tried to get in with tftp 100 times no avail, tried nmrpflash, no avail too

Heard about usb ttl option but in nowhere its 100% well explained, ordered an adapter anyway waiting to arrive.
Any ideas in the meantime?