Note: Install tp-link AC1200 t4u driver for ubuntu

Bought a TP-link AC1200 wifi adapter long before and not used it so far. Yesterday, I find it again when I collected my old stuff. Since my old Dell laptop does not support 5G channel, and its built-in wifi adapter sucks, why not have a try!!!

Searched and tried a lot, and finally, I find the correct one(which works for me). The link is: https://ubuntuforums.org/showthread.php?t=2340769

# Uninstall rtl8812au-dkms if you installed it as other solutions told you
sudo apt-get purge rtl8812au-dkms
# Install the necessary software
sudo apt-get update
sudo apt-get install git dkms

git clone  https://github.com/ptpt52/rtl8812au.git
cd rtl8812au
sudo make -f Makefile.dkms install
sudo modprobe rtl8812au
# Now the hardware should work for you