Revisited: JTAG 'Hacking' of the Original Xbox After 20 Years
2025-01-20
This blog post details the author's successful attempt to 'hack' the original Xbox using its Intel Pentium III CPU's JTAG interface. The original Xbox's security relied on a 512-byte secret bootrom hidden within the NVIDIA MCPX Southbridge. While early researchers considered using the CPU's JTAG capabilities, it was deemed impractical due to the TRST# pin being grounded. The author designed a custom CPU interposer PCB to circumvent this, and using a vintage CodeTAP debugger, successfully dumped the secret bootrom via JTAG, proving a 20-year-old theory. This work is historically significant and provides valuable experience and resources for x86 JTAG research.
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Hardware
Original Xbox