I bought the TP-Link Archer C20 V4, Installed openwrt and tried it out. It is unfortunately not working out for me. The primary issues being,
No support for 5GHz wifi
I have been trying to figure out a way to set it up as a 2.4 Ghz range extender and it's extremely confusing how all of it works.
So, Now I would like to go back to stock firmware. From what I have read so far, I can't simply flash stock firmware over tftp. I need a stripped firmware. I have tried to find a stripped firmware of archer c20 v4 and have came up empty.
I use the tp_recovery.bin from that link and that worked just fine for me.
sidenote:
I downloaded the stock firmware and ran binwalk on it. It had 3 files on it. 1. U-Boot image 2. LZMA compressed data 3. Squashfs filesystem
Then, I checked the tp_recovery.bin and it's structure is exactly the same which makes me wonder if I could've used the stock image from official source as tp_recovery.bin.
I also checked the openwrt_sysupgrade.bin but that one has uboot section stripped out of it. I guess, This could've been done by figuring out offsets and stripping it with dd.
Anyway, Thank you so much! I never could've figured out all of that on my own without having access to stripped images in hand.