OK, not so much the antenna maybe, but possibly the chip inside. IDK. The wire came off the antenna. It required me stripping it and then re-soldering - twice.Nice upgrade! Just wondering... why not at least run El Capitan? It's fully supported, and is an evolution on Yosemite. IMO the best OS for these 09 mini is High Sierra, but that requires a patcher. But it's very easy to do.
It's 100% stable on mine, and performs better than any OS I have ever run on it. It will love that 8GB RAM. It also gets updates until late 2020. Yosemite hasn't had an update since 2017.
BTW... I doubt you broke the antenna. Those pop off the connector very easily. They're a pain to reconnect also, but not impossible or anything. The connector is also very tiny.
Molten metal on which some sort of chip is attached. All I can say is that BT is jumpy. I remember it being smoother when I first brought it out there. I will have to wait and see what happens when I actually start using the keyboard and mouse out there versus just connecting to the Mac's shared drive.
As for El Capitan. I don't know what it is about it, but I don't like it. Pretty much the only reason. There aren't any apps that I'm going to be using this Mac for that Yosemite won't run though and I avoid SIP.