Game Boy,rebuilt.

Nintendo's 1989 handheld: one Sharp CPU, a 160 × 144 screen in four shades, a 32-pin cartridge slot and four AA batteries.

The goal

A new handheld that plays original cartridges: a modern mainboard around a real Game Boy CPU, USB-C charging, a backlit screen and a speaker.

Enter the room

Fig. 01 · Game Boy · front and top, as publishedSizes [11]

What is known.

Read on October 6, 2026. Every line says how it is known and where it comes from.

Reference: From a technical reference written from measurement of the device.
Reported: Reported by the press or by a community project, not by the maker.

CPU: One Sharp 8-bit chip running at 4.194304 MHz, believed to be an SM83 core. A 256-byte boot ROM sits inside it.[1][2]; Reference
Memory: 8 KiB of work RAM and 8 KiB of video RAM, as two external 64-kbit SRAMs.[1][3]; Reference
Display: 160 × 144 pixels in 4 shades at 59.7 Hz, over a 21-pin ribbon: two data bits, a pixel clock, HSYNC and VSYNC.[4][5]; Reference
Cartridge: 32 pins at 1.5 mm: 5 V, PHI, /WR, /RD, /CS, A0–A15, D0–D7, /RES, VIN and GND.[6][7]; Reference
Link port: 6 pins, clocked at 8192 Hz, moving 8 bits per transfer.[6][8]; Reference
Sound: Two pulse channels, one wave and one noise; a mono speaker and a stereo headphone jack.[9]; Reference
Power: Four AA cells, 6 V at 0.7 W. A converter board makes about 4.9 V and an unregulated LCD bias near −18 V.[1][10]; Reference
Size: 90 × 148 × 32 mm, from Nintendo's 1989 manual as Wikipedia relays it.[11]; Reported
Schematics: Traced KiCad schematics, CC-BY-4.0: the mainboard matches DMG-CPU-06 only and the LCD board DMG-LCD-06 only; the power boards (types A to D) and the headphone boards (01 to 03) have their own. The mainboard and headphone boards are also traced net by net over board scans.[12]; Reference

Not published.

What nobody has said in public yet. Each one is a question the room answers by building.

A KiCad layout of the original boards. The traces exist only as drawings over board scans, so footprint positions have to be scaled from them.
How a modern screen keeps the original's timing without dropping frames. That is this room's own problem.

Six milestones.

In order. Each one is reached when its last line is true of the board.

01
Reference capture.
One block diagram and one net list across the boards: the cartridge bus, the LCD ribbon, the link port, sound and power.
Done whenEvery net names the schematic it was read from.
02
Core board.
A real CPU (QFP-80, 0.8 mm) taken from a donor, two 64-kbit SRAMs, the 4.194304 MHz crystal and the 32-pin slot.
Done whenThe open test ROM dmg-acid2 runs from a flash cartridge.
03
Power.
A Li-ion cell with USB-C charging, a 5 V boost converter and a fuel gauge, in place of four AA cells.
Done when5 V holds within 5% from a full cell to an empty one.
04
Display.
A backlit screen driven by a bridge chip that samples the two data bits on the pixel clock and scales by two.
Done when59.7 frames a second, none dropped.
05
Sound and controls.
A speaker amplifier, the headphone jack, eight buttons and the link port.
Done whenTwo units trade data over a link cable.
06
Shell.
The room's own enclosure around the mainboard, built in the Product view, with DRC and ERC clean.
Done whenThe board and its enclosure are ready to order.

Room rules.

For everyone on the board. The board is shared, so most of them are about the others.

No ROMsThis room: Never upload, attach or generate a commercial game, a save or Nintendo's boot ROM. Test with open test ROMs such as dmg-acid2 and the mooneye suite.
No marksThis room: No Nintendo logo, name or shell design on the board or the enclosure. Say “plays original cartridges”, not that it is a Game Boy.
Credit the tracingThis room: The schematics this room starts from are CC-BY-4.0. Keep the attribution with the board.
One board: Everyone builds the same project. Don't duplicate it to work alone; work here, where the others can see it.
Your own thread: Talk to Inky in a chat thread of your own. A new message in a thread can stop the turn already running there.
One long job at a time: An autoroute or a long Inky turn holds the board. Tell the others before you start one.
Undo is shared: The board has one history for everyone. Pressing undo twice takes back a teammate's last edit, so look before you press.
Inky runs on your account: The board is shared; your usage is not. Each person's Inky turns count against their own plan.
Public information only: Work from what the maker published, regulatory filings and open references. No leaked documents, no copied firmware, no logos.
The case needs a paid plan: Every room's last milestone is built in the Product view, which comes with every paid plan and not with the trial. Members on the trial can do every other milestone.

Start from.

Open work that gets the room past a blank board. Check each licence before copying from it.

gb-schematics, traced KiCad schematics (CC-BY-4.0)
The traced DMG-CPU-06, LCD, power and jack boards as KiCad schematics, CC-BY-4.0.
gekkio-kicad-libs (CC-BY-4.0)
KiCad symbols and footprints for the CPU, the cartridge slot and the link port, CC-BY-4.0.
Super DMG-01, a replacement mainboard (CC-BY-SA-4.0)
An open replacement mainboard around a real DMG or SGB CPU, in KiCad. Its licence is CC-BY-SA-4.0, share-alike, unlike the CC-BY schematics.
dmg-acid2 test ROM (MIT)
An open rendering test ROM (MIT) whose reference image shows at a glance whether the picture is drawn right. It does not test timing.

Sources

The technical reference: Pan Docs.

Pocket, Persona, Friend and Game Boy are trademarks of their owners. heypcb is not affiliated with them and no endorsement is implied. Rooms build functionally equivalent devices from public information.

Game Boy,rebuilt.

What is known.

Not published.

Six milestones.

Reference capture.

Core board.

Power.

Display.

Sound and controls.

Shell.

Room rules.

Start from.