RPI3 does not support RTL8811CU Wireless LAN 802.11ac USB NIC dongle out of the box. Guideline to compile by yourself

Install RTL8811CU Wireless dongle on debian based RPI3

# Device 0bda:c811, RTL8811CU Wireless LAN 802.11ac USB NIC
# Drivers for rtl8811CU and rtl8821CU Wi-Fi chipsets.
$ lsusb
# List of supported devices by compiled modules
$ modprobe -c | grep -i 8821cu # search our module

# Thread on forum with this problem (whitebatman saved my day)
1. https://ubuntuforums.org/showthread.php?t=2389602&page=3&p=13772230#post13772230
2. Whitebatman Repo: https://github.com/whitebatman2/rtl8821CU


# How to link and pre compile kernel before compiling driver
https://discourse.osmc.tv/t/gpio-joystick-raspberrypi-kernel-headers/35592/5
0. Before all install:
$ sudo apt-get install build-essential
$ sudo apt-get install libssl-dev

1. sudo apt-get install rbp2-source-4.19.55-6-osmc
2. sudo ln -s /usr/src/rbp2-source-4.19.55-6-osmc /lib/modules/4.19.55-6-osmc/build
3. sudo ln -s /usr/src/rbp2-source-4.19.55-6-osmc /lib/modules/4.19.55-6-osmc/rbp2-source-4.19.55-6-osmc
4. cd /usr/src/rbp2-source-4.19.55-6-osmc
# Run commands
$ sudo make oldconfig  # (on case if error with bison: apt-get install flex bison)
$ sudo make prepare  # (on case if error /bin/sh: 1: bc: not found: sudo apt-get install bc)
$ sudo make modules_prepare

# How to install rtl8821CU driver for (Device 0bda:c811, RTL8811CU Wireless LAN 802.11ac USB NIC)
# make -j4 ARCH=arm (ARCH=arm must be on RPI3)
1. git clone https://github.com/whitebatman2/rtl8821CU
2. cd rtl8821CU
3. Change Makefile to:
CONFIG_PLATFORM_I386_PC = n
CONFIG_PLATFORM_ARM_RPI = n
CONFIG_PLATFORM_ARM_RPI3 = y
4. make -j4 ARCH=arm
5. make install
6. modprobe 8821cu

# How to connect from command line to Wifi
https://gist.github.com/kylemanna/6930087

# How to disable onboard wifi
1. Put to '/etc/modprobe.d/rpi-blacklist.conf'
blacklist brcmfmac
blacklist brcmutil
2. reboot

Thank you! rbp2-source is not available in the kali linux repos I'm using, but I skipped this part and it worked fine

You are welcome.