A developer has successfully reverse engineered the PROM firmware for the Silicon Graphics O2 workstation, unlocking the potential for CPU upgrades that were previously blocked by proprietary firmware limitations. The O2, a Unix workstation from the late 1990s featuring MIPS processors, has long been a target for hardware enthusiasts seeking to push its performance beyond factory specifications. The original 300-400 MHz CPUs could theoretically be replaced with faster 900 MHz RM7900 processors, but this required modifications to the boot firmware that were previously impossible without access to SGI's proprietary source code.

Building on community efforts from the early 2000s, where users successfully upgraded O2 systems to 600 MHz using RM7000C CPUs, the new reverse engineering work creates a pathway for even more ambitious hardware modifications. The key innovation is ip32prom-decompiler, a tool that transforms the binary PROM firmware into human-readable assembly code with extensive annotations. This decompilation process preserves the exact bit-level representation while making the code comprehensible and modifiable.

The decompiler employs sophisticated techniques including constant replacement, memory address labeling, function boundary detection, and comprehensive documentation insertion. These enhancements transform incomprehensible machine code into structured assembly with meaningful labels and comments. The resulting code maintains perfect fidelity to the original binary while enabling developers to understand and modify the firmware's behavior. This breakthrough eliminates the need for SGI's cooperation, as the decompiled assembly can be reassembled into a functional PROM image supporting newer CPU models.