Revert to stock firmware (Tplink Archer C2600)

I got the Tplink Archer C2600 in 2018. I flashed OpenWRT right away, I am in snapshot 19.07. But now I want to switch back to stock firmware; I need to resell it to get a new router. Is there any way to get back to the stock firmware?

https://openwrt.org/toh/tp-link/tp-link_archer_c2600_v1#debricking