ello friends I installed openwrt on my tp link wr741nd but I did not like the version I was using, so I went back to firmware stock (tp link), I always used this firmware and it never gave a problem. But this time when doing the process I can no longer access the router appears this: Does brick my router?
As it appears your router is not bricked. It is possible that your browser is using some old cookies or saved passwords to login to the router page. That's the reason it's displaying wrong username or password page.
In order to fix it you need to reset your router. Turn on the router and wait for it to successfully boot after that press reset button for at least 7 seconds. This will erase all configuration from the router and it will go back to the default settings. After that delete temporary files from the browser including any cookies and then you can access your router again.