Install Mercury USB WiFi AC650M driver on Raspberry Pi

AC650M_RTL8821CU_WiFi.txt

#http://124.244.86.40:8080/wordpress/2020/12/13/%E5%9C%A8-raspberry-pi-%E5%AE%89%E8%A3%9D-mercury-usb-wifi-ac650m-%E9%A9%85%E5%8B%95/ (jan2021)
mkdir -p ~/build
cd ~/build
git clone https://github.com/brektrou/rtl8821CU.git

sudo apt-get install dkms bc vim -y

sudo apt update -y
sudo apt upgrade --fix-missing -y && reboot

cd ~/build/rtl8821CU


sudo vim Makefile
CONFIG_PLATFORM_I386_PC = y
CONFIG_PLATFORM_ARM_RPI = n

Change to

CONFIG_PLATFORM_I386_PC = n
CONFIG_PLATFORM_ARM_RPI = y


sudo cp -v /lib/modules/$(uname -r)/build/arch/arm/Makefile /lib/modules/$(uname -r)/build/arch/arm/Makefile.$(date +%Y%m%d%H%M)
sudo sed -i 's/-msoft-float//' /lib/modules/$(uname -r)/build/arch/arm/Makefile
sudo ln -s /lib/modules/$(uname -r)/build/arch/arm /lib/modules/$(uname -r)/build/arch/armv7l

sudo ./dkms-install.sh
sudo usb_modeswitch -KW -v 0bda -p 1a2b
systemctl start bluetooth.service

sudo vim /lib/udev/rules.d/40-usb_modeswitch.rules

 Before the following line:

LABEL="modeswitch_rules_end"

Insert the following settings

# Realtek 8211CU Wifi AC USB
ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="/usr/sbin/usb_modeswitch -K -v 0bda -p 1a2b"

#
#iw dev
phy#1
	Interface wlan1
		ifindex 4
		wdev 0x100000001
		addr 54:c9...
    
 Bus 001 Device 008: ID 0bda:c820 Realtek Semiconductor Corp. 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x0bda Realtek Semiconductor Corp.
  idProduct          0xc820 
  bcdDevice            2.00
  iManufacturer           1 Realtek
  iProduct                2 802.11ac NIC
  iSerial                 3 123456