Firmware not flashing on TP-Link Archer C20 V4

Installing and Using OpenWrt
1

Hi, I'm new here

I tried flashing OpenWRT to my Archer C20 V4 using the TFTP method, and now the router is in some kind of limbo state? It boots with all of the LEDs on for 1 second, then all of the LEDs turn off and nothing happens

If I connect my computer to one of the LAN ports the LAN LED lights up, and if I connect a network to the WAN port, the WAN LED lights up

Connecting both seems to just passthrough my LAN connection to the WAN connection, as if it was plugged directly to my computer

I have captured the traffic via Wireshark and it does seem to be transferring the tp_recovery.bin file

Here's the Wireshark log https://files.catbox.moe/vztss0.pcapng

2

Here's the tp_recovery.bin file I tried to flash https://files.catbox.moe/3av35v.bin

3

If you think someone will dissect some random firmware file, you're wrong.

How was it created and where did it come from ?

Were you following https://openwrt.org/toh/tp-link/archer_c20_v4 ?

1 Like
4

I took it from here:

https://downloads.openwrt.org/releases/24.10.5/targets/ramips/mt76x8/openwrt-24.10.5-ramips-mt76x8-tplink_archer-c20-v4-squashfs-tftp-recovery.bin

from this guide:

6

Can you point to where it says to use dd? I can't find it

7

Wrong device, never mind.

What IP does you client get ?

8

I set up as static, 192.168.0.66

If it's passing through with both cables connected then it's whatever the WAN DHCP decides I guess

9

Find out, be precise.

1 Like
10

Right now I switched my ethernet ipv4 to Automatic, and connected both cables to the router just to access the internet

12

192.168.88.104, the same as if I just connected the WAN cable directly to my computer instead of the router

13

DHCP doesn't work without the WAN cable connected btw

14

I assume, you’ve got another router (ISP?) upstream?

Otherwise, this won’t make any sense.

15

Yes, sorry for not clarifying, I thought my message made sense as "WAN Cable"

English is not my first language

16

Not really. That doesn’t explain what’s upstream of your router. This could be another router which already delivers a private address, or a modem or router in bridged mode where you’ll get a public address. It’s never good to omit important details.

Nor is it mine…as well as many other helpful people.

Nobody would be offended if one uses a translator because he/she/it isn’t skilled in a foreign language.

17

I meant Yes, there is an ISP router connected to the WAN port of this router

18

I just wonder how you managed it to get the same IP address regardless if you use your C20 or not.

With one exception: You connected both WAN and LAN to the LAN ports of the router, so it just works as a switch. Or you added your WAN in the config to the LAN ports, which will give you the same result.

On an standard installation, you should get an address in the range of 192.168.1.x.

19

Got lucky I guess? Just tried it again and got different IPs from connecting directly vs through the router, I think it is just working as a switch

I can also try flashing it again via TFTP, it transfers the file over but after it finishes it's back to this state

20

I guess, then you’ll need a serial connection (USB-TTL) to your router so you can see what’s happening.

21

I'll order one, I already needed it anyways for something else

I also found another forum post that seems to have the same issue

22

During recovery procedures, there should only be a single network cable connected (the one to the tftp server, maybe with an unmanaged switch inbetween) - specifically wan should not be connected.

(yes, we are all lazy and might try it that way nevertheless, but at the very least when things don't work, reduce the setup to the minimum; it does make sense recovering with the OEM firmware <-- warning, check the size, so you don't flash an oversized image, overwriting irrecoverable wifi calibration data, only do that if you are 101% sure what you're doing).

Looking at the device specs, be aware that ordering a usb2serial adapter costs almost as much as a (better) used/ working device of this device class would, so economically speaking it might be more sensible to look for a replacement than blowing new money into this model.