[fazo96]

When I upload the DD-WRT firmware file it just says "Unable to upgrade" right after the HTTP upload is done.

On my PC I'm running the solus linux distro which does not have any TFTP server packaged so I couldn't just use the TFTP recovery.

The router is on the latest firmware, I also tried a factory reset but the problem persists. I checked and I have the right build, I also tried openwrt and I got the same error.

Maybe I'm missing something, otherwise I'll try to set up the TFTP server at the right IP using a virtualbox VM in bridge mode

If there's no fix then the wiki should be updated since it says you can install dd wrt from the stock web ui.

[bushant]

@ian5142 has a couple of these routers, he may be able to shed some light on this. In the meantime try a different browser and do not use the latest recommended build in the router database (37305). That build has problems on many routers including yours.
https://forum.dd-wrt.com/phpBB2/viewtopic.php?p=1152154#1152154

See the links in white in my sig for latest firmware.
Also be sure to read this:
https://wiki.dd-wrt.com/wiki/index.php/TP_Link_Archer_C7

[ian5142]

First try and downgrade or upgrade the factory firmware (TP-Link). At one point there were some versions of the factory firmware that blocked third party installs. Downgrade/upgrade may solve this.

Then try and flash the factory-to-ddwrt file for your router again, via the GUI.

TFTP server would be the next step. Not all Archer C7's seem to have this feature. I used to have it but now none of my TP-Link routers does.

Server IP (set your computer to this): 192.168.0.66
File name: Depends (enable logging is your best bet).
Be patient, don't reboot the router manually without waiting at least 10 minutes.