I was very angry still, but as this was more income that I'd ever gotten in my life, I shut up and kept on with it.
Until one day. That morning, I was working on my board and connected it over usb for it to boot up. While it did that, I went away to grab one more cable. I was gone only 30 seconds or so. When I came back, there was a strange smell all over the living room. I couldn't place it. But that's when it hit me: it was the board. I injured myself disconnecting the thing, as it was well on its way to catching on fire, around 170°C by then.
I immediately contacted him and told him what happened. He was dismissive and uncaring that I had hurt myself enough that my had is permanently scarred. He didn't bother listening to my arguments that we can't possibly have this happening, ever again, not to me, not to him, not to anyone using the product. Just imagine that thing sitting on the dash of your car catching on fire.
I was ignored and dismissed once again. And I had enough.