3 Questions about getting Wi-Fi working

Digidoc · 2026-07-03 19:23

I have a dual core CPU which is too slow to run Windows. I want to run Q4OS. I fooled with it for many hours trying to get a Realtek adaptor to work. I used [lsusb] and found it uses 0bda:c811. I was just not able to find/download/install anything to make it work.

RTL8811 may be another name, I do not know for sure.

Will an adaptor using: 802.11ac AC600 USB Adapter, and also RTL8811 work with Q4OS?
Will an adaptor with RTL8192EUS work with Q4OS?
Will an adaptor with Tenda U11 AX900 and a .deb package work with Q4OS?

I may order all 3 and try them out. Thanks for any help.

swarfendor437 · 2026-07-05 23:24

Which version of Q4OS are you wanting to run?

Based on the ID of your card I ran a search in Brave Search engine via Mojeek which always brings up an A.I. search result at the top which gave the following:

The 0bda:c811 USB Wi-Fi adapter, manufactured by Realtek Semiconductor Corp., is an 802.11ac NIC that typically requires the rtl8821cu driver on Linux systems.

For Linux kernel versions 6.2 and newer, the device is supported by the rtw88 kernel module with the configuration option CONFIG_RTW88_8821CU. For older kernels, you must manually install an out-of-tree driver.

Installation Options:

Modern Kernel (6.2+): The driver is included in the mainline kernel. Ensure CONFIG_RTW88 and CONFIG_RTW88_8821CU are enabled.

Legacy Kernels: Use a community-maintained driver such as brektrou/rtl8821CU or morrownr/8821cu-20210916.

Clone the repository: git clone https://github.com/brektrou/rtl8821CU.git

Install build dependencies (make, gcc, linux-headers, dkms, bc).

Run the DKMS installer: sudo ./dkms-install.sh

Load the module: sudo modprobe 8821cu

Important Note on USB Modeswitch: Many 0bda:c811 adapters ship in CD-ROM mode by default. You must switch the device to NIC mode using usb_modeswitch before the driver can recognize it.

Install usb_modeswitch: sudo apt install usb-modeswitch (Debian/Ubuntu) or sudo pacman -S usb-modeswitch (Arch).

Switch the mode: sudo usb_modeswitch -KW -v 0bda -p c811

To make this permanent, add a udev rule to /lib/udev/rules.d/40-usb_modeswitch.rules:

ATTR{idVendor}=="0bda", ATTR{idProduct}=="c811", RUN+="/usr/sbin/usb_modeswitch -K -v 0bda -p c811"

Verification: Use lsusb to confirm the device ID is detected and lsmod | grep 8821cu to verify the driver is loaded.
AI-generated answer. Please verify critical facts.

I got a TP-Link T2U working on Q4OS 5.8 using the following guide:

https://community.tp-link.com/en/home/f … yId=395878

It worked instantly - the only thing that did not work was the dongle's green LED but connected instantly to the wifi network once password to router provided.

Last edited by swarfendor437 (2026-07-05 23:30)

Digidoc · 2026-07-06 01:23

For Linux kernel versions 6.2 and newer, the device is supported by the rtw88 kernel module with the configuration option CONFIG_RTW88_8821CU. For older kernels, you must manually install an out-of-tree driver.

I am offline: no sudo, install, git, update. How do I invoke this "configuration option" you mention above? Are there other steps I must also do?

I can use the following command:

/bin/bash -c "$(curl -fsSL https://dandanilyuk.github.io/rtw88_driver_installer/install.sh)"

How can I run this since I am currently offline? Can anyone explain how to get what I need, put on a USB drive, and run it on my offline laptop?

Last edited by Digidoc (2026-07-06 15:24)

hchiper · 2026-07-07 14:05

Digidoc wrote:

/bin/bash -c "$(curl -fsSL https://dandanilyuk.github.io/rtw88_driver_installer/install.sh)"
How can I run this since I am currently offline? Can anyone explain how to get what I need, put on a USB drive, and run it on my offline laptop?

This script requires an internet connection; otherwise, it will generate an error. It automates the download, compilation, and installation of the rtw88 driver. Rather than analyzing this 1,000-line script to answer your question, follow the instructions at https://github.com/lwfinger/rtw88:
- When you see "git clone…", simply transfer the downloaded directory to your offline computer.
- When you see "apt install…", follow the instructions I provided in this discussion where you abruptly gave up: https://www.q4os.org/forum/viewtopic.php?id=6127.

Too bad your computer doesn't have an RJ45 Ethernet port to connect it to your router via cable and access the internet

Digidoc · 2026-07-08 00:06

I bought a cheap wifi dongle from Amazon ($6.99). It is 2-n-1 as it also contains bluetooth. https://www.amazon.com/dp/B0C6915MKL

It says Windows only, but it recognizes and installs fine with Q4OS. It is also single band using 2.4ghz and 150mb transfer speed. For the money, I am not complaining. I am installing Q4OS Plasma now. I ran the DEB script, it complained about DKMS, it isnstalled anyway, but it still does not work.

I am disappointed a driver was not included for 0bda:c800 Realtek.

Last edited by Digidoc (2026-07-08 00:47)

hchiper · 2026-07-08 09:30

Digidoc wrote:

I ran the DEB script, it complained about DKMS, it isnstalled anyway, but it still does not work.
I am disappointed a driver was not included for 0bda:c800 Realtek.

Which "DEB script" are you talking about?
Did you mean the "install.sh" script? As I wrote in my previous post, "This script requires an internet connection."

"it complained about DKMS": maybe it's the reason why your dongle is still not working, but you give no information about that complain, so one can not know.

I don't find any web page for "0bda:c800"; do you confirm it is the exact identifier of your device? From the Amazon page you gave the link, it appears that your new device uses a RTL8723BU. So what?
From IA, the RTL8723BU dates back from 2014 and is almost obsolete. IA also confirms that the "firmware-realtek" is the appropriate package to install.

Double check it is installed, or even reinstall it. Then if you new USB adapter still not works, the only two reasons I can imagine are
- no WiFi connection created to your router (with correct password),
- a hardware failure somewhere in the USB circuitry of your computer.

Digidoc · 2026-07-08 17:10

I consider my Linux knowledge to be at the elementary school level. Please forgive me as I struggle to learn. I now have 2 wi-fi USB; 1 works, the other does not. The 1 not working is: 0bda:c811 USB Wi-Fi adapter, manufactured by Realtek Semiconductor Corp. Despite my attempts and despite advice from here in the forum, it continues to not work. Both my computer and this wi-fi are old and many consider them to be obsolete. These are what I have to work with. I do not fully understand what DKMS is. Now I have internet, I can follow basic terminal commands. Simple steps for me (one at a time) would be highly appreciated. Should I just forget this project and put this adaptor into my Windows only basket of gear?

Last edited by Digidoc (2026-07-08 17:12)

hchiper · 2026-07-08 20:45

Digidoc wrote:

I consider my Linux knowledge to be at the elementary school level. Please forgive me as I struggle to learn. I now have 2 wi-fi USB; 1 works, the other does not. The 1 not working is: 0bda:c811 USB Wi-Fi adapter, manufactured by Realtek Semiconductor Corp. Despite my attempts and despite advice from here in the forum, it continues to not work. Both my computer and this wi-fi are old and many consider them to be obsolete. These are what I have to work with. I do not fully understand what DKMS is. Now I have internet, I can follow basic terminal commands. Simple steps for me (one at a time) would be highly appreciated. Should I just forget this project and put this adaptor into my Windows only basket of gear?

Yes, I think so, since your Internet connection problem appears to be solved.

Q4OS Forum

#1 2026-07-03 19:23

3 Questions about getting Wi-Fi working

#2 2026-07-05 23:24

Re: 3 Questions about getting Wi-Fi working

#3 2026-07-06 01:23

Re: 3 Questions about getting Wi-Fi working

#4 2026-07-07 14:05

Re: 3 Questions about getting Wi-Fi working

#5 2026-07-08 00:06

Re: 3 Questions about getting Wi-Fi working

#6 2026-07-08 09:30

Re: 3 Questions about getting Wi-Fi working

#7 2026-07-08 17:10

Re: 3 Questions about getting Wi-Fi working

#8 2026-07-08 20:45

Re: 3 Questions about getting Wi-Fi working

Board footer