Algorithm puzzles on a whiteboard tell you something. They rarely tell you whether a candidate notices a DMA buffer reused too early. Desktop Leafpoint’s Firmware Team Advisory work often includes rebuilding the interview loop around a small live board.
Keep the board humble
A Nucleo-class board, a blinking LED, a UART, and one deliberately awkward bug are enough. The point is observation: does the candidate read the schematic excerpt, ask about clock sources, and instrument before rewriting?
Score behavior, not speed
We watch for how they narrate uncertainty, whether they check the errata, and if they leave the bench cleaner than they found it. Fast green LEDs with no hypothesis are a weak signal.
Pair the sessions
One interviewer owns the hardware story; another watches collaboration. Candidates who go quiet may still be thinking carefully — give them space before you fill silence with hints.
After the hire
The same board can become an onboarding lab. New engineers reproduce the interview bug in week one, then fix a related issue in your real tree. Continuity beats a one-off spectacle.
If you want help calibrating that loop, request a briefing and mention hiring in your scope snapshot — we treat it as part of firmware team advisory, not a separate product.