System Design (Firmware + BSP Architecture) (60 Questions)

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Section A – Firmware Architecture (1–10)

1.

Design the firmware architecture for an Automotive ECU.

Include:

  • Bootloader
  • Application
  • RTOS
  • Drivers
  • Middleware
  • Diagnostics
  • Application Layer

2.

How would you layer an embedded software architecture?

Explain:

  • HAL
  • MCAL
  • Drivers
  • Middleware
  • Application

3.

How would you organize a large embedded firmware project with more than 500 source files?

4.

How would you design a reusable firmware architecture supporting multiple hardware variants?

5.

Explain your preferred software layering approach.

6.

How would you minimize dependencies between modules?

7.

How would you design a firmware architecture for easy unit testing?

8.

How would you implement dependency injection in embedded systems?

9.

How would you support multiple product variants using the same codebase?

10.

How would you manage configuration across multiple ECU variants?

Section B – BSP Architecture (11–20)

11.

Design a Linux BSP for a custom ARM Cortex-A board.

12.

What components should be included in the BSP?

13.

How would you structure the BSP source tree?

14.

Explain the Linux boot sequence in your BSP.

15.

How would you integrate a new SPI driver?

16.

How would you add support for a new board revision?

17.

How would you manage Device Tree files for multiple boards?

18.

How would you structure board-specific initialization?

19.

How would you debug BSP startup failures?

20.

How would you optimize Linux boot time?

Section C – Bootloader Architecture (21–30)

21.

Design a production-quality automotive Bootloader.

22.

Design a Secure Boot architecture.

23.

How would you implement A/B firmware partitions?

24.

How would you implement rollback protection?

25.

Design a Bootloader supporting:

  • CAN
  • Ethernet
  • USB
  • UART

26.

How would you implement a firmware recovery mechanism?

27.

How would you implement firmware version compatibility checks?

28.

How would you secure Bootloader updates?

29.

How would you implement multi-image Bootloaders?

30.

Design a multicore Bootloader.

Section D – Linux Driver Architecture (31–36)

31.

Design a driver architecture for:

  • SPI Flash
  • EEPROM
  • GPIO
  • Watchdog
  • CAN Controller

32.

How would you organize platform drivers?

33.

How would you structure interrupt handling?

34.

How would you design DMA support?

35.

How would you implement power management?

36.

How would you design a reusable Linux driver framework?

Section E – RTOS Architecture (37–42)

37.

Design an RTOS task architecture for an Automotive ECU.

Tasks:

  • CAN
  • Ethernet
  • Diagnostics
  • OTA
  • Sensor Acquisition
  • Watchdog
  • Logging

38.

How would you assign task priorities?

39.

How would tasks communicate?

40.

How would you prevent deadlocks?

41.

How would you optimize CPU utilization?

42.

How would you monitor system health?

Section F – Communication Architecture (43–48)

43.

Design an ECU supporting:

  • CAN FD
  • Automotive Ethernet
  • SPI
  • I²C
  • UART

44.

How would you separate real-time and non-real-time communication?

45.

How would you prioritize messages?

46.

How would you handle communication failures?

47.

How would you implement redundancy?

48.

How would you support diagnostics over CAN and Ethernet simultaneously?

Section G – Secure Architecture (49–54)

49.

Design a secure firmware update architecture.

50.

How would you securely store cryptographic keys?

51.

How would the HSM integrate with Bootloader and Application?

52.

How would you prevent firmware rollback?

53.

How would you secure debug interfaces such as JTAG/SWD?

54.

How would you secure inter-ECU communication?

Section H – Architecture Scenarios (55–60)

55.

Design an Automotive Gateway ECU.

Requirements:

  • CAN FD
  • Automotive Ethernet
  • OTA
  • Diagnostics
  • Secure Boot
  • Linux

Explain:

  • Software architecture
  • BSP
  • Bootloader
  • Drivers
  • Middleware
  • Applications

56.

Design an OTA architecture for a vehicle with 50 ECUs.

Include:

  • Rollback
  • Recovery
  • Security
  • Logging
  • Version Management

57.

Design an ADAS ECU.

Include:

  • Camera
  • Radar
  • Ethernet
  • Linux
  • RTOS
  • Secure Boot

58.

Design a firmware architecture for an industrial controller supporting multiple communication interfaces, field updates, and strict real-time constraints. Explain how you would separate hardware abstraction, protocol handling, application logic, and diagnostics.

59.

Your company plans to migrate an existing bare-metal firmware platform to Linux while retaining compatibility with legacy hardware. Describe your migration strategy, key architectural decisions, risks, and validation approach.

60.

You are the Technical Lead for a next-generation Automotive ECU.

The requirements include:

  • ARM Cortex-A + Cortex-M heterogeneous multicore
  • Linux on Cortex-A
  • RTOS on Cortex-M
  • Secure Boot
  • HSM
  • OTA/FOTA
  • UDS
  • CAN FD
  • Automotive Ethernet
  • USB
  • SPI Flash
  • eMMC
  • Watchdog
  • Diagnostics
  • Functional Safety
  • Cybersecurity
  • A/B partitions
  • Logging
  • Recovery Mode
  • BSP
  • Linux Device Drivers

Design the complete architecture, covering:

  • Boot flow and chain of trust
  • Software layering (Bootloader, BSP, middleware, applications)
  • Partitioning between Cortex-A and Cortex-M
  • Inter-core communication
  • Driver organization
  • RTOS task design
  • Linux services
  • OTA update flow
  • Security architecture
  • Memory layout
  • Fault detection and recovery
  • Logging and diagnostics
  • Manufacturing and production considerations
  • Testing and validation strategy

Whiteboard Design Questions (Very Common)

Interviewers often ask you to draw and explain:

  1. Complete Boot Flow.
  2. Firmware Architecture.
  3. Linux BSP Architecture.
  4. Device Driver Stack.
  5. Secure Boot Chain of Trust.
  6. OTA Update Flow.
  7. RTOS Task Architecture.
  8. Communication Stack.
  9. Memory Layout.
  10. HSM Integration.

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