This is geared towards gentoo but should work in every system if you have your kernel sources available.

If you come across the notorious hard-to-install AC1200 USB wifi devices and want to get them to work with linux, here is how it goes:

The chipset is a bit of a mystery, this is what lsusb says:

  idVendor           0x0bda Realtek Semiconductor Corp.
  idProduct          0xb812 
  bcdDevice            2.10
  iManufacturer           1 Realtek
  iProduct                2 USB3.0 802.11ac 1200M Adapter
  iSerial                 3 123456

It's actually a 8812BU chipset from realtek. It will not work with a stock kernel and the available drivers usually do not work with a recent kernel (I use 4.19.8-gentoo)

Make sure you have the kernel sources for your current kernel and /usr/src/linux/ points to your current kernel.

You will need to clone the following repo:

git clone https://github.com/cilynx/rtl88x2BU_WiFi_linux_v5.2.4.4_26334.20180126_COEX20171012-5044
cd trl88x*
make
make install

You can test it without restarting if you modprobe 88x2bu. dmesg should show that a new network device was added.