Wifi of rtl8192cu chipset devices has bad drivers by default - instructions of https://github.com/pvaret/rtl8192cu-fixes.git in script

rtl8192cu.sh

#!/bin/bash

#stop script on first error
set -e

#Pre-requisits
sudo apt-get update
sudo apt-get -y install git build-essential dkms #linux-headers-generic 

#Clone this repository:
git clone https://github.com/pvaret/rtl8192cu-fixes.git

#Set it up as a DKMS module:
sudo dkms add ./rtl8192cu-fixes

#Build and install it:
sudo dkms install 8192cu/1.10

#Refresh the module list:
sudo depmod -a

#Ensure the native (and broken) kernel driver is blacklisted:
sudo cp ./rtl8192cu-fixes/blacklist-native-rtl8192.conf /etc/modprobe.d/

wget https://goo.gl/2rFHTF -O 8192fix.sh && chmod +x 8192fix.sh && sudo ./8192fix.sh

Then reboot.