Micron Technology Firmware Test Engineer Intern interview questions

Applied online, receive a phone interview ten days later, it lasts for an hour and asked basic questions cover data structure, operating system, c, python, testing, It went well. Received an second phone interview from HR a week later, asked my visa status, expected pay, when available to work etc. He also asked some simple behavioral questions.This one lasts for 20 minutes. Then one day later, the third phone interview come. It was a mixture of behavioral and technical questions, questions are harder than the first round. I didn't know there is another round of interview so didn't get prepared. One week later, HR told me that they went with another candidate.