Seeking safe installation guidance for OpenWRT on a TP-Link Archer C20 V5 (US version) router

devx · 2025-04-06T14:12:40.814Z

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I found this GitHub repo https://github.com/dxdxdt/tp-link_c20-v5.dev, and this states the following.

512 is the size of header(sizeof(struct fw_header) is 512: exb A, exb B). The actual binary that the hardware loads starts after the header.

196608(0x30000) is the size of the first boot loader region. The TFTP recovery program skips 196608 bytes of the downloaded image when copying into the flash. Stupid design if you ask me. This number(0x30000) appears on the serial output when performing TFTP reset. 0x30000 is probably the size of the first boot loader for all variants. But you can only find this out if you have the serial console. If you think it's not for your variant, well. Shotgun it(trial and error). I highly doubt it's other than 0x30000, though.

The first boot loader never touches its region(0x0 - 0x30000). The first boot loader will always be there to help you(unless you manually modified it). As long as the first boot loader is intact, you can debrick your hw. Cheers.

Should I follow it to extract the bootloader?

brada4 · 2025-04-06T14:23:10.783Z

Dont get creative, use linux like wsl-ubuntu
They have correct point - use start of file from firmware that is already running, fact not in wiki.

devx · 2025-04-06T14:27:58.493Z

i am on linux, acording to the the repo i have chnaged the command to
dd if=stock_firmware.bin of=boot.bin bs=64K count=3 64k x 3=196608 bytes

brada4 · 2025-04-06T14:29:28.019Z

Use exclusively OpenWrt guide.
Did i note to keep creative powers down when dealing with numbers?

devx · 2025-04-06T14:31:18.393Z

Sorry for that, I couldn't find a proper guide. It will be helpful if you can provide a link or something

brada4 · 2025-04-06T14:32:07.820Z

devx:

available here.

I'm unsure

Some smart guy posted it earlier.

devx · 2025-04-06T14:37:24.513Z

I'm really sorry — I was overthinking and didn't realize it was already there. Thank you so much for your patience and help. I’ll follow the official documentation and wiki, and I’ll try to flash the image on my router using TFTP.

brada4 · 2025-04-06T14:49:14.766Z

no problem, id still suggest first method from that wise guys link
https://openwrt.org/toh/tp-link/archer_c20_v5#installing_via_web-ui

devx · 2025-04-06T14:55:42.129Z

I just tried the web ui installation but the image wasn't accepted. TFTP should work, I watched many YouTube videos though, any advice on this?

brada4 · 2025-04-06T15:02:53.301Z

Try to first upgrade to same tplink version via webui and upload openwrt frankenimage after fresh start.

devx · 2025-04-06T15:06:42.786Z

By frnkenimage are you referring to this?

TP-Link image:             tpl.bin
OpenWrt sysupgrade image:  owrt.bin

 > dd if=tpl.bin of=boot.bin bs=131584 count=1
 > cat owrt.bin >> boot.bin

This is used for Webui upgrade from wiki

brada4 · 2025-04-06T15:16:31.523Z

Precisely that.

devx · 2025-04-06T16:48:10.219Z

I Flased the stock OEM. And then flashed the OpenWRT frankenimage but got the same result. The boot.bin wasn't accepted by the device. What should I do now?

brada4 · 2025-04-06T16:57:13.831Z

unaccept the post and wait 24-48h for somebody smarter to jump in.

devx · 2025-04-10T06:13:35.853Z

Hi, thanks for your help! I was able to successfully install OpenWRT on my Archer C20 V5 (US) using a TFTP server.

Initially, I didn’t get access to the Web UI because it was a snapshot build, and I hadn’t included LuCI in my build configuration. However, I managed to install the LuCI package manually by SSH into the router.

Everything seems to be working well now, and I’ve configured it properly. However, I have one issue: my router is dual-band. On the stock firmware, the 5GHz band worked flawlessly, but with OpenWRT, the 5GHz band isn’t showing up. I’ve used the same configuration as the 2.4GHz band (with all defaults), but the 5GHz SSID doesn’t appear on my phone.

Should I create a separate topic for this issue, or could you help me here?

brada4 · 2025-04-10T06:21:49.895Z

5ghz radio requires setting country code and makes you wait 1-10min for radar scan to complete before appearing. if hardware supports the feature you can avoid long waits later enabling background scans like on openwrt one Use background_radar by default - #3 by brada4

devx · 2025-04-10T14:53:25.026Z

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Radio 1 is enabled but on the left-hand side it shows disabled,
I have enabled it and it has been hours, but nothing shows on my phone,

devx · 2025-04-10T14:54:27.782Z

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Heres the configuration on the 5G radio, previously in the country code it was hardware default

mk24 · 2025-04-10T15:02:57.917Z

Choose a specific channel instead of leaving it blank.
If you click scan you should see results from neighbors, if you have any. This demonstrates the radio works. Choose a channel that doesn't have strong neighboring signals.

brada4 · 2025-04-10T15:37:17.970Z

Bangladesh is special, only continuous 3x40Mhz available, check iw list for possible settings.