Street Fighter Alpha 3 Upper

NAOMI GD-ROM multi-region patch

v1.0Sega NAOMI GD-ROM

Game: Street Fighter Zero 3 Upper (Japan, GDL-0002)
Hardware: Sega NAOMI GD-ROM
MAME set: sfz3ugd
Version: 1.0
Updated: 2026-07-10

Screenshots

Japan region: The same patched disc on two BIOS regions. The game's own region-dependent title art shows Street Fighter Zero 3 on a Japanese board and Street Fighter Alpha 3 on a USA board. Note the U.S. copyright line under the American title. — The same patched disc on two BIOS regions. The game's own region-dependent title art shows Street Fighter Zero 3 on a Japanese board and Street Fighter Alpha 3 on a USA board. Note the U.S. copyright line under the American title.

USA region: The same patched disc on two BIOS regions. The game's own region-dependent title art shows Street Fighter Zero 3 on a Japanese board and Street Fighter Alpha 3 on a USA board. Note the U.S. copyright line under the American title. — The same patched disc on two BIOS regions. The game's own region-dependent title art shows Street Fighter Zero 3 on a Japanese board and Street Fighter Alpha 3 on a USA board. Note the U.S. copyright line under the American title.

Original: A USA-region NAOMI BIOS: the original Japanese GD-ROM is refused; the patched image is accepted and loads. — A USA-region NAOMI BIOS: the original Japanese GD-ROM is refused; the patched image is accepted and loads.

Patched: A USA-region NAOMI BIOS: the original Japanese GD-ROM is refused; the patched image is accepted and loads. — A USA-region NAOMI BIOS: the original Japanese GD-ROM is refused; the patched image is accepted and loads.

About this patch

Street Fighter Zero 3 Upper is an enhanced version of Street Fighter Alpha 3 that only came to arcades in Japan, on Sega's NAOMI hardware. Because it's flagged as a Japanese release, a US or Export machine rejects the disc on sight with "THIS GAME IS NOT ACCEPTABLE BY MAIN BOARD."

This patch flips that region flag so the very same disc boots on Japanese, US, and Export systems. Nothing about the game itself changes. On a US or Export machine it now comes up with its Western Street Fighter Alpha 3 branding instead of the Japanese Street Fighter Zero 3, exactly as an overseas release would have.

It is the smallest change possible. Only the region flag is touched, and the game, its language and its settings are left just as Capcom shipped them.

What's changed

NAOMI header region mask: Japan → Japan + USA + Export (one byte in the game header, eight encrypted bytes on disc)
Nothing else. This is a region unlock only, and it does not translate or otherwise modify the game

Download

NAOMI GD-ROM patch, applied to your own disc image

sfz3ugd-multiregion-1.0-chd.zip (5 KB)

SHA-256: 80b168e4e230012957f0202d2cbcc1b0efcb10cd8914841119cb41f5e6b2cd05

The download is a description of the change (8 bytes in track 3) and a script that applies it. You need your own dump of Street Fighter Zero 3 Upper (Japan, GDL-0002): the MAME set sfz3ugd.zip plus sfz3ugd/gdl-0002.chd.

How to apply

unzip sfz3ugd-multiregion-1.0-chd.zip -d sfz3ugd-patch
cd sfz3ugd-patch
python3 apply.py /path/to/sfz3ugd/gdl-0002.chd

Requirements: Python 3, chdman (it ships with every MAME distribution), and about 2.5 GB of temporary disk space. The script verifies your dump, unpacks it with chdman, patches 8 bytes, rebuilds the CHD, and verifies the result against the checksum below. If anything does not match, nothing is kept.

Rename the verified output to gdl-0002.chd inside an sfz3ugd/ folder placed ahead of the stock set in your MAME rompath. MAME reports a checksum warning for the patched CHD. That is expected, and the game boots on Japanese, USA, and Export BIOS regions.

CHD checksums

	SHA-1	Data SHA-1
Original	fceb1014a1c673c91a4529fff75aebfd734d5f4e	471d5f7ddd966f5639312ccd044421f4184dbfc6
Patched	fc009c51d9c9ac8cd72df15ab4196df03130f70b	6948c210393c9de59e84dcc9d0086b6a64873f56

Notes

Applying the patch requires chdman (bundled with every MAME release) and about 2.5 GB of temporary disk space.
MAME reports a checksum warning for the patched CHD. This is expected; the game boots and plays normally.
For optical drive emulators on real hardware, the patched CHD can be unpacked to GDI with chdman extractcd.
You still need the unchanged sfz3ugd.zip (security PIC) alongside the CHD.