Now available

Introducing
A4092

The next generation Zorro III SCSI‑2 controller for the Amiga 4000 and Amiga 3000. Redesigned from the ground up. Fully open source.

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A4092 SCSI-2 Controller — Red PCB with Xilinx CPLD and LSI 53C710 chips, Zorro III edge connector
Evolution

Everything you need.
Nothing you don't.

Building on Dave Haynie's original A4091 architecture with modern components and streamlined manufacturing. Improved compatibility, signal integrity, and performance — in a smaller form factor. 227 components, 8 GALs, 7 hours of hand assembly. We fixed that.

ReA4091

Previous generation

Logic8 × discrete GALs
ROMParallel EPROM
ConstructionThrough-hole + SMD
Design ToolEasyEDA
Build Time~7 hours manual
Components227 (top + bottom)
→

A4092

Next generation

Logic1 × XC95144XL CPLD
ROMSPI Flash (W25X40)
ConstructionFull SMD
Design ToolKiCad
Build TimeMachine assembled
ManufacturingJLCPCB ready
Technical Specifications

Built for performance.
Designed for reliability.

⚡
10 MB/s *

Fast SCSI-2

Synchronous transfers at the maximum Fast SCSI-2 bus speed with full DMA support over the Zorro III bus.

* Maximum theoretical SCSI-2 bus speed. Real-world performance depends on your Amiga model, CPU, and connected SCSI devices.

◈
53C710

NCR SCSI Processor

SCRIPTS-based I/O processor with hardware scatter/gather. The same proven silicon from the original Commodore A4091.

▦
XC95144XL

Single CPLD

All glue logic consolidated into one Xilinx CPLD, replacing eight discrete GAL chips. Cleaner signals, simpler board.

⬡
Zorro III

Full Bus Master DMA

True Zorro III bus master with DMA. Compatible with the Amiga 4000 and Amiga 3000. Requires Super Buster Rev 11, with experimental Buster 9 support.

⊞
SPI Flash

Modern Autoboot ROM

Open source firmware with TD64/NSD64 support for large disks, CDROM boot, and early boot diagnostics menu.

◉
Active

On-board Termination

Integrated active SCSI-2 termination. No external terminators needed for clean bus integrity.

Firmware

Modern firmware,
classic compatibility.

Fully open source firmware that runs on both the A4092 and original A4091 boards.

Large Disks TD64 and NSD64 support for hard disks larger than 4 GB. No more partition limits.
Boot Options CDROM boot support and early boot diagnostics menu accessible by holding the right mouse button during startup.
Software Version 42.36 — AmigaOS drivers, ROM image, test programs, and debugging tools. All on GitHub.
Compatibility Works in the Amiga 4000 and Amiga 3000. Requires Super Buster Rev 11. Zorro II card compatibility improvements in the latest software release. Experimental Super Buster 9 support available — broadening compatibility with more Amigas out there.
Manufacturing SPI flash storage with 4 KB allocated for manufacturing data — assembler identity, PCB metadata, CPLD version, and factory test results.
Product Lineup

Choose your controller.

Three generations of Zorro III SCSI engineering — from faithful reproduction to modern re-implementation.

Sold Out ReA4091 SCSI Controller

ReA4091

The original reproduction

  • ✓ Full-length Zorro III card
  • ✓ 8 × GAL logic chips
  • ✓ Parallel EPROM firmware
  • ✓ Internal + external SCSI
View on GitHub
Sold Out ReA4091 Mini SCSI Controller

ReA4091 Mini

Compact edition

  • ✓ Short Zorro III form factor
  • ✓ Keeps PCI slots free
  • ✓ Same performance as full
  • ✓ Lower shipping costs
View on GitHub
Community

Fully open source.

Hardware, firmware, and tools — all on GitHub. From schematics and gerbers to AmigaOS drivers and diagnostic software. Built by the community, for the community.

Explore the project

The A4092 carries forward the open source tradition of the ReA4091 project. Every schematic, every line of code, every PCB trace — available for inspection, modification, and contribution.

A4092 Hardware Firmware & Drivers CPLD Logic Community Discord
FAQ

Common questions.

What is the A4092? ▼
The A4092 is the next generation of the ReA4091 — a Zorro III Fast SCSI-2 controller for the Amiga 4000 and Amiga 3000. It's based on the original Commodore A4091 architecture by Dave Haynie, redesigned with modern components: a single Xilinx CPLD replaces eight discrete GAL chips, SPI flash replaces the parallel EPROM, and the entire board is full SMD for machine assembly. More details at scsi.me.
Is the project open source? ▼
Yes, completely! Hardware schematics, gerbers, CPLD logic, firmware, AmigaOS drivers, test tools, 3D-printable accessories, manuals, and more are all on GitHub. Contributions are welcome.
Which Amiga models does it work with? ▼
The A4092 works in the Amiga 4000 (desktop and tower) and the Amiga 3000. It requires a Super Buster Rev 11 chip for full performance. Experimental Buster 9 support is also available — if you need it, select the Buster 9 logic option when ordering. If you have a Super Buster 7 (A3000), you'll need to source a Rev 11 upgrade separately.
What's in the box? ▼
Every A4092 ships with: the controller board, a full-color printed manual, custom packaging, internal active SCSI-2 terminator, Zorro bracket, and A4000D mounting bracket. Every board is tested for hours before shipping to ensure a great out-of-box experience.
What SCSI devices are supported? ▼
Any Fast SCSI-2 device — hard drives, CDROM drives, tape drives, Iomega ZIP drives, and more. The firmware supports TD64 and NSD64 for hard disks larger than 4 GB, CDROM boot, and includes an early boot diagnostics menu (hold right mouse button during startup).
Can I order more than one? ▼
Yes! Each order covers one board. If you'd like more than one, simply place a separate order for each. Stock is limited, so order while supplies last.
Can I update the firmware? ▼
Yes. The A4092 uses SPI flash, which is reflashable. Firmware updates are released on GitHub and can be applied without opening the Amiga. The CPLD logic can also be updated if needed.
How do I check my order status? ▼
Visit the Order Lookup page and enter the email you used when ordering. You'll see your order status, serial number, and tracking information once shipped.
Where can I get help or ask questions? ▼
Join our Community Discord — that's the best place for setup help, troubleshooting, and general Amiga SCSI discussion. You can also open an issue on GitHub or send us an email.

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