Need help i upgrade my firmware to openwrt

i update my tp link wr840n v5 software to openwrt now its not showing wifi or also not connecting with laptop via ethernet

This particular model only has 4MB flash storage and has been generally dropped from support after OpenWrt 18.06 (which is EOL and unsupported).

What firmware did you flash (specific filename and/or link) and how did you do it?

thanks for reply i install this one

I have three ISP connections with three routers. The others are big routers, so first, I tested on one of them, but it didn't work. Now, I want to solve this issue first before continuing with the others.

My guess is that you'll need to use the tftp method to try installing the image again since your device is not booting normally. There is information about the tftp details in the v4 version device page -- hopefully it is the same for the v5.

The truth is that installing a long since EOL'd version of OpenWrt on very old hardware isn't really going to be that useful to you, although the debugging of this issue could be handy for learning. Depending on the device, the installation process may be considerably different (some trivially easy, others are more complex).

What are your "big" routers?

first i am trying to fix this and i have xr500 and ax11000 and huawei router v5

This one is supported.

there are a few "ax11000" models by different manufacturers... what is the exact brand/model of this one? And what about the huawei router -- what is the model number on the info panel of this device?

I have tried for nearly 4 to 5 hours, but nothing is working. The log details are not being displayed, so I don't want to take the risk with another router, but thanks for your help.