TP-Link Archer C7 v5 (US) bugs, flash failure? [SOLVED - WPA3 issue]

[agent24]

I just bought an Archer C7 v5 (US) because my old TL-WR1043N/ND v2 started causing interference on the AM radio band and trying to track down that issue and fix it isn't likely to be feasible right now.

I downloaded and installed the latest 1.13.0 version of Gargoyle for the Archer C7 V5, and all seemed well, but halfway through configuring the settings, DHCP and internet connectivity died.

I could still connect to the router if I gave my computer a static IP address, but internet did not work.

I reset and tried to reconfigure the router several times. Every time, it would work for a short time and then once again DHCP and internet connection would just disappear.

I thought I would try re-flashing the router just in case it hadn't worked properly the first time, and now naturally, that didn't work either, and I have a brick.

Assuming I can get the router recovered (who knows?) - is there any known issue/fix for the DHCP and internet failure issue I experienced?

[Lantis]

If you could give a set of exact steps taken that lead to the problem, and a backup of the configuration of the device once it is in the problematic state, i can try to have a look.

[agent24]

Thanks for the reply.

I don't think that there were any exact steps to cause the problem. At first I thought it was when I changed the SSID, but the second time it did it while adding static DHCP assignments. The third time, I had basically completed everything; DHCP, port forwarding, installed Adblock etc etc, it ran fine for 5 minutes and then died again.

Before each try I reset to factory defaults.

On the 4th time I was going to attempt to run it without configuring anything from defaults except the PPPOE connection, but that was when I had the idea to reflash which didn't go well either.

Now I'm stuck with a solid power LED that blinks once at power on then nothing else. If I hold the reset button while powering up I get the WPS LED on for a bit then it goes off. Can't get any other behavior. Can't connect via IP to recovery webpage either, if it has one.

So I guess I'm going to attach to the a serial port next and hope that's still alive...

Is there any info on manually flashing the EEPROM if I have to? I assume it wouldn't be as simple as loading the BIN file into a programmer.

[Lantis]

Have you attempted TFTP recovery?
https://openwrt.org/toh/tp-link/archer_ ... _with_tftp

I would suggest trying without adblock as that will take up significant flash space/memory.
The other thing would be are you setting "enforce DHCP assignments"? That could in theory lock you out.

[agent24]

Thanks, yes TFTP worked. Guess I was overthinking it as usual.
I found this earlier, now back to stock firmware... https://www.reddit.com/r/openwrt/commen ... ir_archer/

Will try Gargoyle again tomorrow.

The first two times I had the issue I hadn't even got far enough to install any extra packages at all. And Adblock is working fine on my older router for years even with half the RAM and hardly any free flash space. So I'd be surprised if it was that.

I'll try a real basic setup tomorrow and post configs if/when it all goes to custard...

Edit: I didn't have "enforce DHCP assignments" turned on at the time (though I do on my old router) but from past experience manually setting the IP in the client or resetting the interface brings the new IP in and everything works. In this case, neither of those ideas solved the problem either.

[agent24]

Decided to just run the router on stock firmware for a day or two to try to rule out any hardware or other issues.

So far I have seen no problems, so I assume the router is functioning OK.

Will try Gargoyle again in the next couple of days, then see if I can get any more information if the previous issue repeats itself.

[agent24]

I have ran the router with stock firmware for 2+ days and seen no issue. I have now just flashed again with Gargoyle 1.13.0.

I have set up only my PPPoE DSL connection, enabled Wi-Fi and set the SSID and WPA2 key. I have changed nothing else from defaults.

So far it's been an hour and nothing has gone wrong (yet?).

I now realise however, last time I actually enabled the WiFi with WPA3, so perhaps that was the problem?

[Lantis]

That is highly likely to be the issue.
Your device wifi hardware is too old to run WPA3 natively, so it offloads all of the cryptographic operations to the CPU, which can’t cope either.

[agent24]

I think I can safely say that the WPA3 option was most likely the issue.

The router had been running for several hours with no issues, the only change; WPA3 was not enabled.

Later, I also disabled IPv6 DHCP as I have no need of it. As of posting this, the router has been up for 48 hours and no problems.

I guess the only real bug here then is that there are options to select WPA3 on a router which doesn't support it.

Hopefully in the next release, this feature will not be an option in these firmware images for older hardware.

[Lantis]

I’ll look into it, but I’m not sure there’s a way to determine if the wifi chipset can hardware WPA3