You need to be prepared for everything you put in CV, they were really straightforward and asking technical stuff even in initial interviews. So try to revise all the content in your CV

4 rounds were taken , all were technical , very deep technical discussion happened. Interview well really went but the HR called me and told that we hired another suitable person and not you. This is the 2nd time I appeared for ARM withing quick time , first time they did the same thing , interview was fantastic but they wrote me that your work expectation is different so we cant hire you. Although in the interview we had the things cleared. Just dont know why they keep doing this. Very disappointed. Never ever going to apply there now.