Marcel Pflug of the Game Boy Museum built GB Test Lab, a free ROM that turns any flash cartridge like an EverDrive into a full diagnostic suite for the original Game Boy DMG-01. Booting a copy of Tetris does not confirm a working unit. Intermittent faults, key bounce issues, and a dead link port can all survive that test undetected.
GB Test Lab goes further than Nintendo's own DMG-AGING-01 factory validation cart and further than most homebrew alternatives. It tests CPU, RAM, interrupts, button connectivity, key bounce timing, and runs a two-console Pong session over the link cable to stress that port directly. It also validates GB Printer communication. Results are saved per unit and persist on flash carts with battery backup.
The ROM is free. The original article is worth reading for how Pflug structured the autonomous versus user-input test split, and for the built-in component reference baked into the ROM itself, including how to interpret specific failure symptoms. That last detail makes this a diagnostic tool, not just a pass-fail checker.
[READ ORIGINAL →]