Reddit reviews Making Embedded Systems: Design Patterns for Great Software

It's not the easiest thing to break into, but possible. I think the reason for that is because it's hard to find entry level embedded jobs because of the level of investment before someone can operate. For example, you can hire an entry level web developer, and within 3-4 months they will be ready to go on small tasks. Embedded industry, the upfront learning can take much longer (imo). On top of that, the amount of things that can go wrong, and the amount of knowledge to debug when shit hits the fan, is way higher. But it sounds honestly like you've done some of that investment already, and that's attractive. When I was hired as an embedded engineer, I didn't know what SPI/I2c was, how to read a schematic, etc.

The hard thing is that the simplest thing in embedded world can take a while to learn, and once you learn it you don't think it's good enough, or "oh that's easy'. Those are the building blocks that are needed, and while they're not exactly difficult it takes time to wrap your head around trading bits down a wire during SPI. Reading datasheet, using the awful ides that come in the world, the lingo, all of that is simple stuff but takes time to learn, and it sounds like you've invested enough to know some of the stuff you're talking about. An employor knows you don't have to spend time coming up to speed with. In short, those low level protocols are knowledge worth bragging about.

You say you have a C.S. degree, but that is very much worth something. I work alongside electrical engineers and people with non CS degrees, and I shine when it comes to design patterns and figuring out alternative methods when tackling a problem with constraints. It comes in handy and is not useless, in the end, you're still writing software. I have also found that I have an easier time switching layers and environments than my peers who are non-CS, and want to stay in one area of problem.

I guess this is a random stream of consciousness, but in the end, it's possible. It sounds like you're on the right track and would be able to keep up during an interview. Apply and see what happens, you more than you think. And what you don't know, is okay! Be honest with yourself, you've done what you can.

I really recommend a book for all learner's of embedded systems, Making Embedded Systems. All of that stuff is important, and during my embedded career I look back through it and say "wow, this information was in this book the entire time". Lots of gold.