Ask HN: Anyone broken into low level / embedded development self taught?

I'm, starting to genuinely consider the switch as it's something I've been interested in for years, but I lack the acedemic credentials. I'm confident of my abilities to teach myself much of it, but anything closer to electrical engineering or DSP, I'm a bit iffy about. Has anyone broken into some form of low level development without a degree or perhaps with an irrelevant degree?