● Covered by 1 source · 1 reportLow impact1 neutral
Photon-Emission-Guided Laser Fault Injection Bypasses RP2350 Secure Debug
Key points
- Photon-emission microscopy located a debug-enabling register on the RP2350.
- Laser pulses restored debugger access to the chip's Secure world.
- A secret was recovered from one-time-programmable memory during a rescue reset.
- The attack requires physical access, destructive preparation, and $250,000 in equipment.
Bypassing Permanent Debug Disablement
Researchers successfully bypassed the permanent debug-disable settings on the Raspberry Pi RP2350 microcontroller. They used photon-emission microscopy to identify a specific register responsible for enabling debug features. Subsequently, precisely aimed laser pulses at two nearby positions on the chip restored debugger access to the Secure world, despite the debug functionality being permanently disabled.
Secret Recovery from OTP Memory
With the re-enabled debug access, and after initiating a rescue reset, the researchers were able to recover a secret from the chip's one-time-programmable (OTP) memory. The reset procedure temporarily halted the chip before its firmware could apply a runtime lock, allowing the OTP page to remain readable in the Secure state.
RP2350 Security Model and Context
The RP2350 is Raspberry Pi's dual-core microcontroller, featuring hardware security measures such as secure boot, Armv8-M TrustZone, permanent debug-disable settings, and glitch detectors. Raspberry Pi has actively engaged researchers through its RP2350 Hacking Challenges to evaluate these protections, with the A4 revision being the version tested in this research. The permanent security configuration and boot public key fingerprints are stored in OTP memory, which is organized into 128-byte pages protected by persistent hardware locks.
Attack Requirements and Limitations
The described attack is highly specialized and has significant prerequisites. It necessitates physical access to the device, destructive preparation of the chip, and approximately $250,000 worth of laboratory equipment. These requirements make the attack impractical for widespread exploitation, indicating a high barrier to entry for potential adversaries.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Primary sources
GitHub Ledger-Donjon/scaffold GitHub raspberrypi/pico-bootrom-rp2350 GitHub raspberrypi/rp2350_hacking_challengeReporting from
Researchers used photon-emission microscopy and laser fault injection to re-enable debug access on a Raspberry Pi RP2350 microcontroller, even after debug features were permanently disabled. This method allowed them to recover a secret from one-time-programmable memory by exploiting a timing window during a rescue reset. The attack requires specialized equipment and physical access, limiting its practical exploitability.