February 8, 2026
PROM night, but make it firmware
Reverse Engineering the Prom for the SGI O2
Vintage SGI “boot brain” cracked — fans dream of 900MHz glow-up
TLDR: An enthusiast cracked the SGI O2’s boot firmware into editable form, potentially enabling long-desired 900MHz CPU upgrades. Commenters split between cheering the craft, urging Ghidra, and wondering if this unlocks real homebrew or just nostalgia—either way, vintage hardware just got a fresh shot at life.
PROM night just got rowdy: a retro hacker built a tool to decompile the SGI O2’s boot firmware (the tiny startup program), making a mod-friendly image that can be reassembled exactly. Translation: the long-teased 900MHz upgrade for this 90s workstation might finally be more than a myth. Cue the comment fireworks. One camp cheers the craftsmanship, with devs swooning over readable labels and constants, while another shrugs: “Is there any actual cool homebrew?” asks nebula8804, side-eyeing the museum vibes. The PC crowd parachutes in with “This is just BIOS modding,” and userbinator says: please, use Ghidra. That sparks a mini turf war: DIY reverse-engineer cred vs polished off-the-shelf decompilers. Meanwhile, the_biot wants nicer C output and faster reading; hinkley drops a dad-joke heard ’round the thread: “Oh, the PROM, not the prom,” and the room loses it. There’s even a moonshot wishlist: unixhero dreams of IBM mainframe microcodes being next. The vibe? Equal parts jubilation, nitpicking, and cosplay-level nostalgia. Whether you’re chasing raw speed or retro romance, the takeaway is simple: with SGI long gone, fans are now the firmware team — and the 900MHz glow-up suddenly feels within reach.
Key Points
- •A developer reverse engineered the SGI O2’s IP32 PROM and created a decompiler that outputs modifiable assembly and rebuilds a bit-identical image.
- •The effort aims to enable support for a 900 MHz PMC-Sierra RM7900 CPU upgrade, previously blocked by unmodifiable PROM firmware.
- •Prior community upgrades swapped in a 600 MHz RM7000C CPU without requiring any firmware or software changes.
- •The decompiler improves readability by labeling addresses, replacing known constants, adding comments and function descriptions, and marking function bounds.
- •With SGI defunct and source unavailable, the decompiled, rebuildable PROM removes reliance on vendor assistance for firmware modifications.