RAK2245 for helium
step1 : Download and install Raspbian Stretch or Buster LITE
step2 : Use "sudo raspi-config" command, enable spi and i2c interface.
step3 : Clone the installer and start the installation.
$ sudo apt update; sudo apt install git -y
$ git clone https://github.com/RAKWireless/RAK2245_for_helium.git ~/RAK2245_for_helium
$ cd ~/RAK2245_for_helium
$ sudo ./install.sh
More things can be found here: https://forum.rakwireless.com/t/helium-hotspot-version-firmware-for-rpi-3-4-rak2245-pi-hat/1697