It was quite a long interview process at five rounds in total. All interviewers were welcoming and kind. I did not get an offer and did not get a helpful explanation of why

The interview process was incredibly smooth. 5 rounds -- recruiter screen, HM, technical, interview loop with bar raiser, hardware engineer, and senior engineer on the team, then a final round with the director of engineering. I was asked about my technical experience and background, various technical questions related to embedded firmware concepts. Process took a few weeks since I had a 1 week work trip in the middle of it. I found out within 1 business day after each round if I was passed on to the next round. Everyone was highly talented, humble, and friendly. Ultimately accepted offer, seems like a great team to work with.