Went through three rounds of interviews:
Questions were related to basic C programming and microcontrollers. Programming questions were conducted using an online whiteboard.
Endianness, bit manipulations, interrupts.
The following metrics were computed from 2 interview experiences for the Apple Firmware role in United States.
Apple's interview process for their Firmware roles in the United States is fairly selective, failing a large portion of engineers who go through it.
Candidates reported having very good feelings for Apple's Firmware interview process in United States.