Nighthawk R8500 bricked after flashing firmware V1.0.2.116_1.0.90

So, I'm not the first one to run into this problem with this version of the firmware.
I read Netgear kb about TFTP2, I пще a recommendation for a tftp client from Windows10, but my problem is that the upload speed is too slow, about 40-70 Kbit/sec. The process for the tftp win10 client never ends, TFTP2 tried to send the firmware, but stopped with an error about an unreachable server (something like this one). Where is the problem? Who knows, maybe?