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Photon-Emission-Guided Laser Fault Injection Enables RP2350 Secure Debug

2026-09-18 | original

read original get Raspberry Pi RP2350 Pico 2 Board → more articles

Why This Matters

This research demonstrates that even hardware billed as securely locked down can be compromised through sophisticated physical attacks like photon-emission-guided laser fault injection, highlighting the limits of silicon-level security guarantees. It matters to the tech industry because it shows how a well-funded, patient attacker with lab-grade equipment can bypass permanent debug-disable protections on widely used microcontrollers like Raspberry Pi's RP2350, informing risk assessments for embedded and IoT security.

Key Takeaways

Researchers used differential photon-emission microscopy to pinpoint the debug-enable register, then used laser pulses to flip the two bits needed to restore Secure debug access on an RP2350 A4 chip.
After regaining debug access via a rescue reset, they extracted a secret from OTP memory before the runtime lock could be applied, exposing a timing window vulnerability.
The attack is highly resource-intensive, requiring physical chip access, destructive sample preparation, and roughly $250,000 in laboratory equipment, making it impractical for casual attackers but relevant for high-value targets.

Worth a Look

Raspberry Pi RP2350 Pico 2 Board — If you're diving into the security architecture of the RP2350, having your own Pico 2 board on hand makes it easy to experiment with its Secure Boot, TrustZone, and OTP features firsthand. It's the same chip discussed in this deep dive into laser fault injection and debug security, letting hobbyists and researchers alike explore microcontroller security concepts hands-on.

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Differential photon-emission microscopy localized debug enable register activity and narrowed the laser search before SWD-guided injection set the two bits required to restore Secure debug on an RP2350 A4.

TL;DR

— Photon-emission microscopy allowed us to locate a register responsible for the enabling of debug features on the Raspberry Pi microcontroller.

— Laser pulses at two nearby positions then restored debugger access to the chip’s Secure world, even though debug had been permanently disabled.

— Using that access after a rescue reset, we recovered a secret from one-time-programmable memory. The reset halted the chip before firmware could apply its runtime lock, so the page stayed Secure-readable.

— The attack requires physical access, destructive preparation, and approximately $250,000 of laboratory equipment.

The RP2350 security model

The RP2350 is Raspberry Pi’s dual-core microcontroller: each processor socket can select either an Arm Cortex-M33 or a RISC-V Hazard3 core at boot. Its hardware security features include:

Secure boot, which authenticates signed firmware against public-key fingerprints provisioned in One-Time Programmable memory (OTP)

The Armv8-M TrustZone, which separates Secure and Non-secure execution states

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Explore topics: rp2350 raspberry pi laser fault injection secure debug photon-emission microscopy