To tell the truth, the threshold of this industry is relatively high, and now companies generally don't need 5 1 to do projects. If you have a little foundation, I suggest learning arm, and whether you run os or not is much better than 5 1. It is difficult, but it is not impossible. I learned electronic information (I only learned 5 1 at school), and now the cortex-M3 used by the company for projects has to be adapted from scratch. Although it's just streaking with your arms.