MAME's Caps0ff dissolved chip lids and read arcade ROMs under a microscope

The Multiple Arcade Machine Emulator community preserves thousands of arcade games across hundreds of chipsets — but DRM code on some chips stopped the ROM files from being copied, leaving those titles undumped. The workaround is blunt and brilliant: decap the chip. Stripping the cap with nitric acid and acetone exposes the circuitry; some chips then yield to quick soldering, while non-rewritable Mask ROMs can be read visually, their 0s and 1s sitting in plain sight under magnification.

An earlier crowdfunded decapping wave dumped chips from Bubble Bobble, Galaga, Arkanoid and Street Fighter EX before collapsing in 2015 amid allegations that a key member had vanished with dozens of rare chips. The Caps0ff project took up the mantle, raising money to buy and decap hundreds of undumped chips and publishing breakdowns for Bad Dudes, Mortal Kombat 4 and Toaplan shooters.

For Fujitsu-made chips in Sega's Virtua Racing, computer vision couldn't reliably extract the data, so Caps0ff built a crowdsourced transcription tool: volunteers read 1s and 0s off gridded close-ups of the die. The first chip was fully transcribed by 88 volunteers in about 15 hours.

DRM defeated electrical dumping, but the data still physically exists as visible silicon features.

Acid decapping is expensive and slow, so the cost was socialised through crowdfunding.

Mask ROM bits can be read optically, turning a hacking problem into a transcription problem.

Human eyes beat the team's computer-vision algorithms — 88 volunteers finished a chip in 15 hours.

Preservation beats protection when the medium is physical: any secret stored in plain silicon can eventually be read by patient eyes and acid.

Caps0ff continued decapping hundreds of chips with tooling improvements promised for future transcriptions. The effort echoes the Apple II preservation scene — and makes the point that no DRM scheme survives a dedicated group of historically minded fans with enough time.