First interview round was a general interview of 30 min. Second interview round was a technical interview of 1 hr. At the end of the first interview round, the interviewer told me the second round would focus on runtime implementation of algorithms and questions about the c language. However the second round interview was nothing like the first round interviewer told me to study. Specifically, the second round was implementing a bare metal driver with no regard to the runtime of the driver. And outside of using c to implement the driver, there was very few questions about c as a programming language. Otherwise though, both interviewers were very pleasant to talk to.