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RTL8812AU Driver Guide (AWUS036ACH)

一句話定位（One-liner）: The Realtek RTL8812AU is the legendary 2×2 dual-band chipset inside the AWUS036ACH — the adapter from every Kali tutorial you have ever watched. It is not in the Linux kernel, so you build the rtl8812au driver once with DKMS and it survives every kernel update.

Concept: the most famous Wi-Fi hacking chipset​

The RTL8812AU drives the AC1200 AWUS036ACH with a high-power (500 mW) radio and two external antennas. Its fame comes from the aircrack-ng community: years of pentest work hardened the out-of-tree driver for exactly the two things Kali needs — monitor mode and packet injection.

Why is it not in the kernel? Realtek never upstreamed a clean driver; the kernel keeps a stub (rtl8812au in staging/) with no monitor support. The community driver (aircrack-ng/rtl8812au) replaces it. The cost is that you must build it once — the DKMS system then recompiles it automatically on every kernel update, so the "one-time build" really is one time.

Prerequisites​

  • Any recent Linux (Ubuntu 20.04+ / Kali / Debian)
  • Build tools + internet: sudo apt install -y build-essential dkms git
  • sudo access
  • AWUS036ACH

Step 1: Remove the (useless) kernel stub​

Some distros ship a Realtek stub driver that grabs the adapter and refuses monitor mode. Unload it first:

sudo modprobe -r rtl8812au 2>/dev/null

(If the command errors "not found", great — no stub present. 2>/dev/null hides the noise.)

Step 2: Build the community driver with DKMS​

cd /opt
sudo git clone https://github.com/aircrack-ng/rtl8812au.git
cd rtl8812au
sudo make dkms_install

Expected output:

Kernel preparation unnecessary for this kernel.  Skipping...
...
DKMS: install completed.

Verify the module is registered with DKMS:

dkms status

Expected output:

rtl8812au/5.6.4.2, 6.8.0-51-generic, aarch64: installed

Step 3: Load it​

sudo modprobe 8812au
iw dev

Expected output: an Interface wlan0 (or wlan1) appears. If you have the stub loaded again after reboot, blacklist it:

echo "blacklist rtl8812au" | sudo tee /etc/modprobe.d/alfa-8812au.conf

and add the real module to auto-load:

echo 8812au | sudo tee /etc/modules-load.d/alfa.conf

Step 4: Monitor mode + injection​

sudo airmon-ng check kill
sudo airmon-ng start wlan0
sudo aireplay-ng --test wlan0mon

Expected output:

PHY	Interface	Driver		Chipset
phy0	wlan0		8812au		Realtek Semiconductor Corp. RTL8812AU
...
12:34:56  Injection is working!
12:34:56  30/30:  100%

That 30/30 line is the AWUS036ACH doing what it is famous for.

Step 5: Back to managed mode​

sudo airmon-ng stop wlan0mon
sudo systemctl restart NetworkManager

Troubleshooting​

SymptomCauseFix
make dkms_install fails with "No rule to make target"Repo snapshot older than your fresh kernelsudo git pull && sudo make dkms_install again
Build fails: missing headersHeaders not installedsudo apt install linux-headers-$(uname -r)
Adapter only in managed modeKernel stub grabbed it firstBlacklist rtl8812au (Step 3) and reboot
Injection 0/30Channel with no AP / driver quirksudo iw wlan0mon set channel 6; git pull the driver; retest
Adapter vanishes after rebootModule not auto-loadedecho 8812au | sudo tee /etc/modules-load.d/alfa.conf
dkms status shows Error after upgradeRebuild failed silentlysudo dkms autoinstall

References​