A hardware hacker extracted a password from a managed switch by tracing SPI flash instruction reads, bypassing locked debug ports. Targeting a GoodTop GT-ST024M switch with a Realtek RTL8372N chip, they sniffed XIP execution from an external QSPI Flash to reconstruct firmware flow without direct debugging.

The 8051-based firmware uses code banking, complicating reverse engineering with tools like Ghidra. By capturing SPI traffic during boot and password entry, the author diffed traces to locate the password check logic. This method offers a practical workaround for devices where debug interfaces are disabled or unavailable.

For hardware analysts, this demonstrates how instruction tracing via logic analyzers can substitute for debug access. The SLogic16U3 analyzer proved capable of capturing 60 MHz SPI, highlighting affordable tools for embedded security research. Future work may involve automating trace analysis for similar embedded systems.