Hi @woozle , thank you for your feedback.

# 1

when I run lsusb, I get:

Bus 002 Device 007: ID 0bda:c820 Realtek Semiconductor Corp. 802.11ac NIC

# 2
when I google for: Linux driver 0bda:c820 I found the following website

h... //forums.linuxmint.com/viewtopic.php?t=405157

I run following commands:

sudo apt update
sudo apt install build-essential git dkms
git clone https://github.com/brektrou/rtl8821CU.git
cd rtl8821CU
chmod +x dkms-install.sh
sudo ./dkms-install.sh
sudo modprobe 8821cu

Now it works. Linux Mint recognizes the USB Wifi device.

But the speed is very slow.

- Onboard Wifi: 2.4GHz => Download: around 40MBit

- TPLink USB Wifi: 2.4GHz => Download: around 10MBit

- TPLink USB Wifi: 5GHz => Download: around 40MBit

When I test the 5GHz Speed on my Mac, I get 250 MBit.

Both computer are on the same table.

Any Idea how I can increase the speed? 

  @KalemKutu 

Can you please place the computer with the T2UB Nano very close to the Wi-Fi router and then test the speed again?

If the speed goes up when the computer is adjacent to the Wi-Fi router, then it is a reception issue.

If the speed remains roughly the same, even when the computer is near the Wi-Fi router, then it is likely a driver issue.

What you could try is to uninstall brektrou's driver and install the one maintained by morrownr instead. ( https://github.com/morrownr/8821cu-20210916 )
 

  @woozle 

Thank you sooo much! :)

Let me describe the outcome: 

# Using the initial driver https://github.com/brektrou/rtl8821CU.git:

- When I was in my office (doors are open) around 6m distance, the download speed was x

- When I get close to the wifi router (10 cm) , the download speed went up to 2x

# Using your suggested driver https://github.com/morrownr/8821cu-20210916:

On each location, the download speed is around 1,5 faster than values above. Its amazing ! 

So the driver you recommended is the best one!

Kalem

PS: For those who might be interested: 

sudo apt install git dkms
cd ~
git clone https://github.com/morrownr/8821cu-20210916.git
cd 8821cu-20210916
chmod +x install-driver.sh
sudo ./install-driver.sh

--- 

At the end I was asked to edit options.

I did not add/change anything, just closed the settings.

Finally I rebooted my notebook!

  @KalemKutu I have a question about the driver for this product. I am new to Linux (I use Mint which is expected because I'm in this forum rn) but I don't know much about how these operating systems work, especially software and/or driver downloads on Linux. I just bought the AC600 archer nano and got it today because the laptop that I put Linux on I decided to leave as a dualboot with windows; however, Linux refuses to acknowledge the WiFi adapter that's built into my laptop so I decided to get the usb (I have no idea if it's supposed to work or not since Linux won't even recognize the built-in one). I followed all of your instructions (and the other person's too) which worked like a charm (thanks), but I ran into an odd situation where secure UEFI did something with the installation of the driver and it still doesn't work after installing it. I don't know what to do/what I did wrong but at least my laptop isn't bricked... do you have any ideas/suggestions?

  @hayd188 

Hi hayd188, I am not an expert. No idea what even your question means.

But i asked your question to Artificial Intelligence, and here is the answer.

###

It sounds like you're dealing with two potential issues:

1. Secure Boot (UEFI): Linux distributions like Mint often have trouble with drivers when Secure Boot is enabled. The Secure Boot feature prevents the operating system from loading drivers that aren't signed, which can be the case for some third-party drivers, especially for WiFi adapters.

   To fix this, you can try disabling Secure Boot in your BIOS/UEFI settings. This usually resolves the issue of drivers not working. Here's how you can do that:

   • Restart your laptop and enter the BIOS/UEFI settings (usually by pressing a key like F2, Esc, or Del while booting).
   • Look for the Secure Boot option, which is often in the "Security" or "Boot" tab.
   • Disable it, save your changes, and reboot.

   Once Secure Boot is disabled, try reinstalling the driver again.

2. Built-in WiFi Adapter: It's a bit odd that Linux isn't recognizing your built-in WiFi adapter. You might want to check which WiFi chipset your laptop uses. You can do this by running the following command in the terminal:

   bash

   lspci -nnk | grep -i network -A3
    

   This will show the network adapter info, and you can look up whether Linux supports it or if you need a specific driver.

If disabling Secure Boot doesn't solve the issue, let me know the result of the above command, and we can dig deeper into finding the right driver for both your built-in and USB WiFi adapters.

 ###

Good Luck!

  @KalemKutu Thank you for replying so fast! Unfortunately, after disabling secure boot, nothing has happened still. I did go ahead and do the second thing that you asked about but I don't know what it's meant to mean, so I'll upload a screenshot for your convenience.