I have had problems, stock firmware not working from webpage, and the stripped firmware too!
Here how I solved it..
https://www.friedzombie.com/tplink-stripped-firmware/download.php?d=Archer-C7-V2i renamed the bin to stripped.bin
I put stripped.bin into /tmp/ from WinSCP (192.168.1.1 with root and the pass you choose)
then in Putty connect to SSH and run these commands:

login as: root
Pre-authentication banner message from server:
| DD-WRT v3.0-r40559 std (c) 2019 NewMedia-NET GmbH
| Release: 08/06/19
| Board: TP-Link ARCHER-C7 v2
End of banner message from server
[email protected]'s password:
==========================================================
___ ___ _ _____ ______ ____ ___
/ _ \/ _ \___| | /| / / _ \/_ __/ _ __|_ / / _ \
/ // / // /___/ |/ |/ / , _/ / / | |/ //_ <_/ // /
/____/____/ |__/|__/_/|_| /_/ |___/____(_)___/
DD-WRT v3.0
http://www.dd-wrt.com
==========================================================
BusyBox v1.31.0 (2019-08-06 03:19:04 +04) built-in shell (ash)
[email protected]:~# md5sum /tmp/stripped.bin
[email protected]:~# mtd -r write /tmp/stripped.bin linux
Unlocking linux ...
Could not unlock MTD device: linux
linux: Not supported
Writing from /tmp/stripped.bin to linux ... [w]
[email protected]:~#
I was told not to use mtd -r write as it bricked someones Archer C7.. but I did anyway, and it worked!