Application Guide

How to Apply for Senior Hardware Security Engineer

at Lime

🏢 About Lime

Lime is a leader in micromobility, offering shared electric scooters and bikes in hundreds of cities worldwide. Working here means contributing to sustainable urban transportation while tackling unique hardware security challenges at scale—from firmware integrity in thousands of field-deployed devices to physical attack resistance in embedded systems.

About This Role

As a Senior Hardware Security Engineer, you'll safeguard Lime's fleet of IoT-connected vehicles against physical and firmware-level attacks. Your work directly impacts rider safety, data privacy, and operational reliability by hardening secure boot, implementing runtime protections, and conducting hands-on security assessments like side-channel analysis and fault injection.

💡 A Day in the Life

A typical day might involve reviewing a new hardware design for security flaws, then heading to the lab to set up a fault injection campaign on a prototype board. After analyzing results, you'd collaborate with firmware engineers to harden the secure boot implementation, and later automate a script to test future firmware builds for common vulnerabilities.

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Interview Prep

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🎯 Who Lime Is Looking For

  • Has 5+ years in hardware/firmware security with deep experience in embedded systems—ideally in IoT, automotive, or consumer electronics.
  • Hands-on with lab equipment: oscilloscopes, logic analyzers, fault injection tools (e.g., ChipSHOUTER, laser), and side-channel measurement setups.
  • Strong firmware reverse engineering skills (Ghidra, IDA Pro) and ability to develop custom tooling for automated security analysis.
  • Familiar with secure boot, TEEs, hardware root of trust, and threat modeling for connected devices—preferably with experience in compliance standards like NIST or FIPS.

📝 Tips for Applying to Lime

1

Highlight specific projects where you performed side-channel analysis or fault injection—mention tools and outcomes (e.g., 'extracted AES key via SPA on ARM Cortex-M').

2

Tailor your resume to show experience with firmware update integrity and secure boot on resource-constrained devices, as Lime's scooters have limited compute.

3

Mention any work with automated security tooling or CI/CD integration for firmware analysis—this shows you can scale security across Lime's fleet.

4

Include examples of collaboration with hardware or firmware engineering teams to implement security recommendations, as the role requires cross-team work.

5

Research Lime's specific hardware platforms (e.g., Segway Ninebot-based) and reference them in your cover letter or interview to show genuine interest.

✉️ What to Emphasize in Your Cover Letter

['Emphasize your hands-on experience with physical attack assessment and how it applies to protecting IoT devices in the field.', "Show understanding of Lime's scale: thousands of devices deployed in harsh environments—connect your security work to reliability and safety.", 'Demonstrate ability to build security tooling and automate testing, which is critical for maintaining security across firmware updates.', 'Express passion for sustainable transportation and how hardware security enables trust in shared mobility systems.']

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🔍 Research Before Applying

To stand out, make sure you've researched:

  • → Read Lime's engineering blog and any security-related announcements to understand their tech stack and security culture.
  • → Review publicly available teardowns or security analyses of Lime scooters (e.g., from security conferences or forums).
  • → Familiarize yourself with Lime's compliance requirements, such as GDPR, CPNI, or any industry standards for IoT security.
  • → Look into Lime's fleet management system and how firmware updates are deployed—this will help you discuss update integrity.

💬 Prepare for These Interview Topics

Based on this role, you may be asked about:

1 Describe a time you performed fault injection on an embedded device—what were the challenges and how did you mitigate them?
2 How would you architect secure boot for a battery-powered scooter with limited flash and RAM?
3 Explain your approach to threat modeling a connected vehicle platform—what are the top risks for Lime's scooters?
4 How do you balance security with performance and cost constraints in embedded systems?
5 Walk through a firmware reverse engineering project: tools used, vulnerabilities found, and recommendations made.
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⚠️ Common Mistakes to Avoid

  • Submitting a generic cover letter that doesn't mention hardware security or IoT—this role is highly specialized.
  • Overemphasizing software security without demonstrating embedded or physical security experience—the job requires lab work.
  • Neglecting to mention relevant tools and lab equipment in your resume—use specific names like 'ChipWhisperer' or 'JTAGulator'.

📅 Application Timeline

This position is open until filled. However, we recommend applying as soon as possible as roles at mission-driven organizations tend to fill quickly.

Typical hiring timeline:

1

Application Review

1-2 weeks

2

Initial Screening

Phone call or written assessment

3

Interviews

1-2 rounds, usually virtual

✓

Offer

Congratulations!

Ready to Apply?

Good luck with your application to Lime!

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