<SOLVED> Unable to use Realtek RTL8811AU Wireless Adapter

[ThreadHazard]

Hi, I've tried Linux once in the past, Ubuntu, and had the same issue. My Realtek Wireless Adapter, Chipset RTL8811AU wont work. I've tried 4 or 5 different drivers by downloading them manually on a different machine, then installing them using the readme, then earlier today I moved my computer to the router and set up ethernet so I could use git and followed some of the solutions on this forum, 4 or 5 more solutions after a reinstall. None of them have worked, so I've resulted to making my own thread.

I'm running Linux Mint 20.2 Cinnamon.

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System:
  Kernel: 5.4.0-90-generic x86_64 bits: 64 compiler: gcc v: 9.3.0 
  Desktop: Cinnamon 5.0.7 wm: muffin 5.0.2 dm: LightDM 1.30.0 
  Distro: Linux Mint 20.2 Uma base: Ubuntu 20.04 focal 
Machine:
  Type: Desktop Mobo: ASRock model: B450M Pro4-F serial: <filter> 
  UEFI [Legacy]: American Megatrends v: P2.00 date: 12/16/2019 
CPU:
  Topology: 6-Core model: AMD Ryzen 5 2600 bits: 64 type: MT MCP arch: Zen+ 
  rev: 2 L2 cache: 3072 KiB 
  flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm 
  bogomips: 81438 
  Speed: 1403 MHz min/max: 1550/3400 MHz boost: enabled Core speeds (MHz): 
  1: 1423 2: 1381 3: 1383 4: 1375 5: 1463 6: 1533 7: 1378 8: 1470 9: 1491 
  10: 1378 11: 1547 12: 1450 
Graphics:
  Device-1: AMD Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] 
  vendor: Sapphire Limited driver: amdgpu v: kernel bus ID: 06:00.0 
  chip ID: 1002:67df 
  Display: x11 server: X.Org 1.20.11 driver: amdgpu,ati 
  unloaded: fbdev,modesetting,vesa resolution: 1280x720~60Hz 
  OpenGL: renderer: Radeon RX 580 Series (POLARIS10 DRM 3.35.0 
  5.4.0-90-generic LLVM 12.0.0) 
  v: 4.6 Mesa 21.0.3 direct render: Yes 
Audio:
  Device-1: AMD Ellesmere HDMI Audio [Radeon RX 470/480 / 570/580/590] 
  vendor: Sapphire Limited driver: snd_hda_intel v: kernel bus ID: 06:00.1 
  chip ID: 1002:aaf0 
  Device-2: AMD Family 17h HD Audio vendor: ASRock driver: snd_hda_intel 
  v: kernel bus ID: 08:00.3 chip ID: 1022:1457 
  Sound Server: ALSA v: k5.4.0-90-generic 
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet 
  vendor: ASRock driver: r8169 v: kernel port: f000 bus ID: 04:00.0 
  chip ID: 10ec:8168 
  IF: enp4s0 state: up speed: 1000 Mbps duplex: full mac: <filter> 
  Device-2: Realtek 802.11ac NIC type: USB driver: usb-network bus ID: 1-7:4 
  chip ID: 0bda:c811 serial: <filter> 
Drives:
  Local Storage: total: 3.87 TiB used: 9.59 GiB (0.2%) 
  ID-1: /dev/sda vendor: A-Data model: SX850 size: 238.47 GiB 
  speed: 6.0 Gb/s serial: <filter> rev: 7ANR scheme: MBR 
  ID-2: /dev/sdb vendor: Seagate model: ST2000DM008-2FR102 size: 1.82 TiB 
  speed: 6.0 Gb/s rotation: 7200 rpm serial: <filter> rev: 0001 scheme: MBR 
  ID-3: /dev/sdc vendor: Seagate model: ST2000DM008-2FR102 size: 1.82 TiB 
  speed: 6.0 Gb/s rotation: 7200 rpm serial: <filter> rev: 0001 scheme: MBR 
Partition:
  ID-1: / size: 233.24 GiB used: 9.58 GiB (4.1%) fs: ext4 dev: /dev/sda5 
Sensors:
  System Temperatures: cpu: 35.4 C mobo: N/A gpu: amdgpu temp: 39 C 
  Fan Speeds (RPM): N/A gpu: amdgpu fan: 819 
Repos:
  No active apt repos in: /etc/apt/sources.list 
  Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list 
  1: deb http://packages.linuxmint.com uma main upstream import backport #id:linuxmint_main
  2: deb http://archive.ubuntu.com/ubuntu focal main restricted universe multiverse
  3: deb http://archive.ubuntu.com/ubuntu focal-updates main restricted universe multiverse
  4: deb http://archive.ubuntu.com/ubuntu focal-backports main restricted universe multiverse
  5: deb http://security.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
  6: deb http://archive.canonical.com/ubuntu/ focal partner
Info:
  Processes: 290 Uptime: 17m Memory: 15.57 GiB used: 1.36 GiB (8.8%) 
  Init: systemd v: 245 runlevel: 5 Compilers: gcc: 9.3.0 alt: 9 Shell: bash 
  v: 5.0.17 running in: gnome-terminal inxi: 3.0.38 

[sleeper12]

With secure boot disabled, do one line at a time:

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sudo add-apt-repository ppa:kelebek333/kablosuz
sudo apt-get update
sudo apt install rtl8821cu-dkms 

Reboot

[ThreadHazard]

Failed on first command.

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You are about to add the following PPA:
 PPA for Realtek wifi drivers

If you installed your system in UEFI mode, you must disable secureboot for modules installed by dkms after installation.

You can check installation mode with following command.

[ -d /sysfirmware/efi ] && echo "EFI" || echo "BIOS"

You can check status of secure boot with the following command.

mokutil --sb-state
 More info: https://launchpad.net/~kelebek333/+archive/ubuntu/kablosuz
Press Enter to contiue or Ctrl+C to cancel

Executing: /tmp/apt-key-gpghome.xQWHyWFhwn/gpg.1.sg --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys F30D3DBFB7534F670B44C71923E50C670722A6D9
 keyserver recieve failed: General error

Executed when connected via ethernet.

[sleeper12]

Did you disable secure boot?

[ThreadHazard]

Yes.

[sleeper12]

See if this works, one line at a time:

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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 

Reboot

[sleeper12]

If that doesn't work, do:

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 sudo apt-key adv --keyserver hkps://keyserver.ubuntu.com:443 --receive-keys F30D3DBFB7534F670B44C71923E50C670722A6D9 

Then try again:

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sudo add-apt-repository ppa:kelebek333/kablosuz
sudo apt-get update
sudo apt install rtl8821cu-dkms 

Reboot

[ThreadHazard]

First one worked, wireless adapter works now, thanks! But, sudo apt update gave an error since It was refusing to grab the PPA repo.

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Reading package lists... Done                                                
W: GPG error: http://ppa.launchpad.net/kelebek333/kablosuz/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 23E50C670722A6D9
E: The repository 'http://ppa.launchpad.net/kelebek333/kablosuz/ubuntu focal InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

Is there a way to stop this from returning whenever I update repos?

[sleeper12]

Try:

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 sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 23E50C670722A6D9 

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 sudo apt update 

[ThreadHazard]

All commands returned without issue
Thanks for all your help, have a good weekend.

[sleeper12]

Good. That repo should have worked, but the missing key must have messed it up. Well, no matter now.

[motoryzen]

All commands returned without issue
Thanks for all your help, have a good weekend.

So I'd rather ask a possibly dumb question than to make a dumb assumption. Given what you said to Sleeper12, does that mean via wireless connection..you're able to do all your normal stuff in the internet?

If yes, please go back and edit your original post's Subject line to include <Solved> in there somewhere so others can see you're good to go

Hopefully that's the case

[ThreadHazard]

Oh, yeah, sorry. Thanks for the reminder. Just edited the subject now.