Raspberry Pi 3 + Realtek 802.11ac (rtl8812au)

realtek-rtl8812au

#!/bin/bash

sudo apt update
sudo wget https://raw.githubusercontent.com/notro/rpi-source/master/rpi-source -O /usr/bin/rpi-source && sudo chmod +x /usr/bin/rpi-source && /usr/bin/rpi-source -q --tag-update
sudo apt-get install bc git -y
rpi-source
git clone https://github.com/gnab/rtl8812au.git
cd rtl8812au
sed -i -e 's/CONFIG_PLATFORM_I386_PC = y/CONFIG_PLATFORM_I386_PC = n/g' Makefile
sed -i -e 's/CONFIG_PLATFORM_ARM_RPI = n/CONFIG_PLATFORM_ARM_RPI = y/g' Makefile
make
sudo insmod 8812au.ko
sudo cp 8812au.ko /lib/modules/$(uname -r)/kernel/drivers/net/wireless
sudo depmod
cd ..
rm -r linux-* realtek
reboot

i can't enable monitor mode... any suggestions
ip link set wlan1 down
iwconfig wlan1 mode monitor doesn't work