Low-level software understanding: interrupt handling, memory constraints, timing, RTOS, concurrency, synchronization, bootloader, peripheral interfacing
Embedded design & architecture: how you structure firmware, abstraction vs performance, communication protocols (UART, SPI, I²C, CAN, etc.)
Debugging & troubleshooting: how you approach diagnosing hardware/software issues, logs, oscilloscopes, breakpoints
Past project depth: they may ask you to present or deep dive into your embedded work
Behavioral / teamwork: how you handled conflicts, cross-discipline teams (HW / mechanical / QA), tradeoffs