Hello. I bought a TL-WR840N (v6.0) router to use as repeater, I had the same model before because my internet ISP installed it for free, they took it away after I switched companies though.
So, I installed it and got into it's panel and saw the design was different from that old model I had, I thought it was a firmware thing so I went ahead and tried to update it.
The router didn't accept the firmware (Yes, I made sure the router version is 6.0 and the firmware version is 6.0), so I searched deeply into the topic and found out you can force flash a firmware using TFTP, that's what I did, after some time trying to figure out the TFTP IP it tries to connect (192.168.0.225), I got the router to connect to my PC's TFTP server and it requested for the tp_recovery.bin file, I placed it in the folder and I saw the upload progress, then after it was done (took like 2 seconds) my router's lights went off and they don't turn on anymore, not even the power light, I have no idea why and I can't find anything related in the internet.