This is a simple Rak831 + Raspberry Pi 3 configurator that allows to quickly replace global_conf.json with the desired band defaults (taken from TTN's configurations), and local_conf.json with typical arguments. It's meant to be used after installing ic880a-gateway and for reconfiguring a gateway.

The SD card that comes with the Rak831 tends to have issues, so I prefer to download a fresh Raspbian image and follow this configuration guide.

These are a series of typical configuration steps for a Rak831 based gateway.

First, modify your SD boot partition to get wifi and ssh access by creating an empty file boot/ssh and a wpa_supplicant configuration file boot/wpa_supplicant.conf with your wifi configuration (change country code, ssid and psk accordingly):

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=CL

network={
        ssid="your-ssid"
        psk="your-password"
}

Now boot your gateway to configure it.
Start by running sudo raspi-config and changing your password and configuring localisation, enabling SPI at the interfaces and expanding your root filesystem.
If you are using a GPS, then also disable serial login shell and enable hardware serial at the interfaces options.

Install necessary packages:

apt-get install git
apt-get install dirmngr

Get the ic880a-gateway code:

git clone -b spi https://github.com/ttn-zh/ic880a-gateway.git
cd ic880a-gateway

Open start.sh and change reset pin from 25 to 17, then install with sudo ./install.sh.
This will install default configurations at /opt/ttn-gateway/bin. You may override them by hand or using this program by running sudo ./rak831rpi. Check Build and Usage sections for instructions on building and using this program.

Finally, install and configure an optional gateway bridge (use https://www.loraserver.io/lora-gateway-bridge/overview/downloads/ for loraserver), and restart your services. Be sure to check correct instructions and keys, but for lora-gateway-bridge it should look something like this:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1CE2AFD36DBCCA00
sudo echo "deb https://artifacts.loraserver.io/packages/2.x/deb stable main" | sudo tee /etc/apt/sources.list.d/loraserver.list
sudo apt-get update
sudo apt-get install lora-gateway-bridge

Configure lora-gateway-bridge:

sudo nano /etc/lora-gateway-bridge/lora-gateway-bridge.toml

Now restart:

sudo service ttn-gateway restart
sudo service lora-gateway-bridge restart

If you are cross compiling, you need to have Go installed in your computer to build this program; if you're compiling on the RPi, Go needs to be installed there. There are no dependencies apart from the stdlib other than golang.org/x/sys/unix to allow setting the hostname. If you don't have it, get it with:

go get golang.org/x/sys/unix

This is the recommend way of building the program. Run make rpi to compile for the Raspberry Pi 3 B+ from your laptop. Just change GOARM at the Makefile for other versions of the RPi.
After building, copy the binary and the bands dir to your RPi:

scp rak831rpi pi@some-ip:~/
scp -r bands/ pi@some-ip:~/

If you're compiling directly, just run make from the repository to build the binary rak831. The bands dir is available with the repository.

Run ./rak831 -h to check the flags:

Usage of ./rak831:
  -alt int
    	ref altitude (default 600)
  -band string
    	band for global_conf.json: AS1, AS2, AU, CN, EU, IN, KR, RU, US (default "AU")
  -down int
    	udp down port (default 1700)
  -eth string
    	eth interface name (default "eth0")
  -gc string
    	global conf path (default "/opt/ttn-gateway/bin/global_conf.json")
  -gpso string
    	options are gps, fake and none (default "gps")
  -gpsp string
    	gps tty path when using a gps
  -host string
    	name to set machine's hostname
  -lat float
    	ref latitude (default -33.433567)
  -lc string
    	local conf path (default "/opt/ttn-gateway/bin/local_conf.json")
  -lng float
    	ref longitude (default -70.6217137)
  -server string
    	server to forward packets to (default "localhost")
  -up int
    	udp up port (default 1700)
  -wlan string
    	wlan interface name (default "wlan0")

If no host argument is given, you'll be prompted to enter your hostname.
The program will print your Gateway's ID (e.g., Your Gateway ID is A0D6BFFFFEB5CEE2), replace global_conf.json and rewrite local_conf.json (make sure it exists first, which should be true after running the ic880a-gateway/install.sh).