@airtonvfilho 

Once downloading the firmware file it is zipped so that needs to be extracted.

Once the zip file is extracted you will end up with a folder that has a zip file in it.

When logged into the router you would upload the .bin file.

Look on the sticker label to make sure the country code matches the firmware which should be (US) in this case.

@Tony thank you, but it is still not working

@airtonvfilho 

If you log into the Archer C80 and go to Advanced > System > Firmware Upgrade. Select "Check for Updates" under online upgrade, does that indicate there is an update, or are you already up to date?

@Tony it indicates that I'm already up to date

but here's the thing: the firmware that I'm using was deleted of the firmware download page of Archer C80, as it was confirmed in this post I made https://community.tp-link.com/en/home/forum/topic/250786

so I thought that if there's a new firmware I should be able to download it, right? since the firmware I'm using now it's not even avaliable for download

@airtonvfilho 

I've seen an instance like that previously with a Deco firmware release which explains when uploading the latest on our site is actually a previous release from what you have.

In the meantime, I would check (weekly) to see if there is a re-release of firmware then update to that.