Ledger Donjon bypasses Raspberry Pi RP2350 debug

Hardware security is only as strong as its weakest architectural override, proving that triple-redundant OTP storage cannot compensate for single-point-of-failure control registers lacking spatial redundancy.

• –**Architectural mismatch**: While Raspberry Pi utilized majority-voting redundancy across multiple OTP rows for critical security flags, the mutable DEBUGEN override register lacked parity or voting logic, leaving an open door to physical state manipulation.
• –**Guided localization workflow**: Combining differential photon emission microscopy with real-time SWD polling provides an effective methodology for navigating complex dies without proprietary layout blueprints.
• –**Rescue reset blind spot**: Unrestricted pre-boot rescue resets halt execution in boot-ROM wait loops before defensive firmware can tighten soft locks, leaving default OTP permissions vulnerable to external extraction.
• –**High physical barrier**: The attack requires destructive backside decapsulation, specialized expertise, and roughly $250,000 in lab equipment, meaning mass IoT deployments face negligible risk from non-nation-state adversaries.