Domoticz

So I had to do an unforeseen complete re-install of my RPi, since it stopped working out of the blue, and I don't have enough knowledge to fix something like that.
Now I'm trying to get Domoticz back up and running, for which I want to use a Razberry. The issue comes in linking ttyAMA0 to ttyUSB20 (or anything else for that matter).
I followed this guide, which I remember using the last time I set up my RPi.
The issue is, that I can't seem to access ttyAMA0. I've looked in the /dev folder, and it's just not there, so when I try to link it to any ttyUSBx, it just won't do anything that works.
Why can't I see/access ttyAMA0? I know I had issues with this part the last time I did this, but I don't remember how I fixed this.

So I found this one out myself, with some help on an other forum.

Apparently, in Raspbian Jessie 1.9.x (and up probably), the GPIO serial port has been disabled by default. I found this guide, which basically describes nothing more then the following:

• Edit the config.txt file:

• Add or change the following line (also make sure it's not commented out):

And that's basically it. Make sure to save and reboot, and you should have access to ttyAMA0 again. Be aware: on the RPi2, ttyAMA0 is the GPIO serial port. On the RPi 3, ttyAMA0 is bluetooth (port?), and ttySO is the GPIO serial port.

Also note that you can use /dev/ttyAMA0 directly, but I think that it's only available on the beta chain. I had huge problems using an alias (/dev/ttyUSB20), where Domoticz would regularly lose contact with the RaZberry board