Can you download a driver and then move it?

Digidoc · 2026-05-31 23:22

I seem to be stuck. I have a desktop and plugged in a wifi-usb. I used lsusb to find a list of the devices, and found it was made by Realtek. It fails to work on several versions of Linux [Q4OS Trinity and Plasma, LMDE 7, Free10 and FreeXP]. I see instructions to use sudo and apt but those commands only work if you already have an internet connection.

Is there a source for a driver package? Can this be downloaded on a different computer? Can these files be transferred to a USB, and then taken back to my Q4OS machine for installation? I fail to understand a way to solve this problem. Advice please?

[Tiny11 loads and finds the correct driver]

Last edited by Digidoc (2026-06-01 04:11)

hchiper · 2026-06-01 06:44

If you know the name of the package that provides your driver, you can use another computer with the same architecture (i386 or x64) running the same version of Q4OS or Debian and run
$ apt-get download <package>

Then copy it to your desktop and install it with one of the commands:
$ sudo apt install ./<package> # if the package is in your working directory; in this case, "./" is mandatory.
$ sudo apt install <path-to-package> # otherwise.

If that package depends on other ones (you'll know at install time), you'll have to repeat the procedure (which might be recursive) for the latter.

Digidoc · 2026-06-01 13:40

I appreciate your reply. This seems beyond my skill level (for now). I gave up and installed Windows instead. Now I need to upgrade the memory. 2gb barely runs Windows but I know Linux can be happy with either 2 or 4 installed. I plan to try another wi-fi soon. If it works, then perhaps using it will allow me to install this odd-ball driver.

leon212 · 2026-06-02 19:02

Yes, you can download the required driver or firmware packages on another PC, copy them to a USB drive, and install them on the Q4OS machine. First, post the output of `lsusb`. "Realtek" alone isn't enough to identify the correct driver. Once the exact chipset is known, it will be much easier to point you to the right package and offline installation method.

Digidoc · 2026-06-02 19:50

Thank you. I ordered another 2gb of memory to install (4gb total). I plan to re-install Q4OS Plasma.
[lsusb] reports my device is Realtek 0bda:ac811

I found instructions for this driver here: https://www.tekbyte.net/installing-wifi … -0bdac811/

I used the following commands:

sudo su
sudo apt update && sudo apt upgrade
sudo apt install build-essential git dkms
cd /tmp && git clone https://github.com/brektrou/rtl8821CU.git

I have it downloaded. [ls] shows the files are there.
I used Dolphin to copy the folder rtl8821CU from the /tmp folder to my external USB storage drive. All Good.
I took the USB storage to the other Q4OS, and used the following commands:

sudo su
sudo chmod +x dkms-install.sh
sudo ./dkms-install.sh

Problem is, the script failed at lines 17 18 and 19. Advice or suggestions are welcome.

Last edited by Digidoc (2026-06-03 00:20)

Attachments:

Wi-Fi needed.png, Size: 44.88 KiB, Downloads: 27

Digidoc · 2026-06-08 13:32

In the failed script, here are the 3 lines where it fails:
dkms add -m ${DRV_NAME} -v ${DRV_VERSION}
dkms build -m ${DRV_NAME} -v ${DRV_VERSION}
dkms install -m ${DRV_NAME} -v ${DRV_VERSION}

Last edited by Digidoc (2026-06-10 18:48)

hchiper · 2026-06-08 15:18

Digidoc wrote:

my device is Realtek 0bda:ac811
No other ideas?

It seems that the package needed for 0bda:c811 is `firmware-realtek`.
Check if it is installed: type `apt list firmware-realtek` in a terminal and look whether you see "installed" at the end of the line output.
If it is not installed see my post #2...

Digidoc · 2026-06-11 01:24

I used the command:
apt list | grep "realtek"
It reports [installed, local]

Still no connections. What now please?

I am back to running live and have not re-installed Q4OS. My machine is a Dell Vostro 420; Core2Duo @3Ghz; 4gb memory, 1tb HDD.
I would like to download using Q4OS (or Windows) and then take the downloaded drivers to the Dell to install them there.
2 screen shots are attached. I am running live on my desktop. By using the ethernet connection, I was able to:

sudo apt update
sudo apt install build-essential git dkms bc
git clone https://github.com/brektrou/rtl8821CU.git
by changing to the folder rtl8821CU.git and ls, I can see the downloaded files. I can copy the folder to USB to take back to my Dell Vostro machine. Now, I am unsure what steps to take next.

Thanks.

Last edited by Digidoc (2026-06-11 02:32)

Attachments:

Q4S-001.png, Size: 70.05 KiB, Downloads: 15

Q4OS-002.png, Size: 10.79 KiB, Downloads: 12

hchiper · 2026-06-11 07:11

Digidoc wrote:

git clone https://github.com/brektrou/rtl8821CU.git
by changing to the folder rtl8821CU.git and ls, I can see the downloaded files. I can copy the folder to USB to take back to my Dell Vostro machine. Now, I am unsure what steps to take next.

I can't say more than the detailed instructions available on that website.
But given that your hardware is not recent, I believe that you don't need more than the installed `firmware-realtek` package.

What are the output of these commands?
- $ inxi -Nxxx
- $ sudo rfkill

Digidoc · 2026-06-11 10:27

Attached is a screenshot from your command: [inxi -Nxxx]
Your second command does not do anything.

PLEASE: I have mild dementia which seems to be getting worse. I ask your understanding as I struggle with life.

Allow me to recap my problem.

A)) I have a USB wi-fi not supported by any of 5 Linux distros.
B)) This is identified as: Realtek 0bda:c811
C)) I think I have the needed driver downloaded to: adminq@debian:~/rtl8821CU$
D)) This folder contains 19 files.
E)) Currently running live on a different computer where the ethernet is working.
F)) Running: [sudo ./dkms-install.sh] I get the error: Error! DKMS tree already contains: rtl8821CU/5.4.1 You cannot add the same module/version combo more than once.
G)) Also the error: Error! Your kernel headers for kernel 6.12.88+deb13-amd64 cannot be found at /lib/modules/6.12.88+deb13-amd64/build or /lib/modules/6.12.88+deb13-amd64/source.
Please install the linux-headers-6.12.88+deb13-amd64 package or use the --kernelsourcedir option to tell DKMS where it's located.
Finished running dkms install steps.

I am at an impasse, I do not know how to continue. ✦ Mike ✦

Last edited by Digidoc (2026-06-11 12:20)

Attachments:

Q4OS-003.png, Size: 27.24 KiB, Downloads: 20

hchiper · 2026-06-11 19:12

Digidoc wrote:

Attached is a screenshot from your command: [inxi -Nxxx]
Your second command does not do anything.

These results seem strange:
1. from inxi output, no driver is associated to your WiFi-USB, although firmware-realtek is installed;
2. rfkill doesn't detect it.

I don't know whether your failed command with dkms has interfered.
If possible, undo what you have done with dkms (I don't know how, I never used dkms, it is not even installed on my system), try to reinstall firmware-realtek, reboot (maybe unnecessary) and see if the two commands above give normal results.

Digidoc · 2026-06-12 01:15

I have decided to abort and give up. I returned to Windows 11 and installed it instead. If the Q4OS team decides to address this driver issue in the future, I do plan to give it another try. I use a desktop for stationary computing [Tiny11], I use 2 laptops when I am moving around. 1 is Tiny11, the other is Q4OS. I feel mainline companies like Realtek should be supported right out of the box. I installed, I ran live, I installed again. No matter what I tried, I could not make it work. Perhaps a future release will include these drivers and I can try it again. I have Q4OS working fine on 5 other computers. Alas, not on this one.

End of this thread.

Q4OS Forum

#1 2026-05-31 23:22

Can you download a driver and then move it?

#2 2026-06-01 06:44

Re: Can you download a driver and then move it?

#3 2026-06-01 13:40

Re: Can you download a driver and then move it?

#4 2026-06-02 19:02

Re: Can you download a driver and then move it?

#5 2026-06-02 19:50

Re: Can you download a driver and then move it?

#6 2026-06-08 13:32

Re: Can you download a driver and then move it?

#7 2026-06-08 15:18

Re: Can you download a driver and then move it?

#8 2026-06-11 01:24

Re: Can you download a driver and then move it?

#9 2026-06-11 07:11

Re: Can you download a driver and then move it?

#10 2026-06-11 10:27

Re: Can you download a driver and then move it?

#11 2026-06-11 19:12

Re: Can you download a driver and then move it?

#12 2026-06-12 01:15

Re: Can you download a driver and then move it?

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