On Debian/Ubuntu/Kali/other debian based distributions for PC you don't need modprobe and monstart/monstop commands, also when using external wifi cards on a Raspberry Pi device
*For raspberry pi zero w, zero 2 w, 3 and 4 ( excluding the 5 you can run the below commands after you've patched the wireless firmware and the kernel, aplicable only for the internal wifi card )
sudo chmod +x wifi_deauth.sh
sudo chmod +x monstart
sudo chmod +x monstop
sudo modprobe brcmfmac
sudo ./monstart
sudo ./monstop
sudo ./wifi_deauth.sh rpi
run without rpi argument for Debian/Ubuntu/Kali or other debian based distributions for Desktop or Raspberry Pi devices with an external wifi card
Run this tool on your own networks, this is an educational tool, not intended for doing any harm. I will not be responsable for any misuse of the tool.