Macintosh IIfx upgrades

Open hardware SCSI emulator with SD-backed storage, optional Wi-Fi networking, and host-side management tools.

For this system (exact model): The official compatibility list names the Macintosh IIfx.

Current seller checks on 2026-07-27 found a $39 internal 50-pin Pico 2 W kit, a $49 assembled external DB-25 model, a $49 PowerBook model, and a $59 assembled Ultra Narrow 50-pin model at authorized seller ToTs RETRO. JCM also carried assembled Ultra hardware and model-specific Macintosh adapters. Prices, stock, included media, and support differ by seller. Ultra models require Berg or Molex power and cannot run from SCSI termination power. The initial Ultra hardware release is not yet open hardware, although its firmware remains GPL; the project says hardware licensing will open later.

Open 64-pin ROM SIMM with selectable 32-bit-clean System 6 and System 7.1 ROM disks for six 68030 Macintosh models.

For this system (exact model): The IIfx is explicitly supported. Use either custom image or the unmodified IIsi ROM; the supplied unmodified IIx ROM is not compatible with this model.

The assembled Tindie module was out of stock on 2026-07-24 and had been sold out since May 7, 2025. Hardware, software, and fabrication files remain public. Most tested 68030 accelerators work, but some 68040 accelerators do not; select the stock IIsi or IIx ROM when the custom image is incompatible. Only 8 MB of the 16 MB flash can be selected at once, with the computer powered off before changing the switch.

Recreates the Macintosh IIfx logic board with new board files, schematics, a parts list, and rewritten PAL logic.

For this system (exact model): The project is explicitly a Macintosh IIfx logic-board recreation. A complete build requires the board, every listed component, programmed replacement PALs, assembly, inspection, and testing.

This is an advanced noncommercial board-build project, not an assembled product. The recreated PALs need suitable 16V8 or 20V8 devices. Low-power ATF16V8B parts do not work, and ATF16V8C parts may be problematic.

Replace a Macintosh ROM SIMM with reprogrammable flash for custom ROMs and, with 2 MB of flash, a bootable ROM disk.

For this system (exact model): The product listing and project documentation explicitly support the Macintosh IIfx as a programmable replacement ROM SIMM.

The GGLABS Tindie store was taking a break on 2026-07-27, but EconoSimm remains buildable from published files. EconoSimm requires a roughly 1.2 mm PCB so it fits the ROM socket, four compatible PLCC-32 flash chips, and a standard flash programmer with a PLCC32-to-DIP adapter. Its author says the BMOW SIMM programmer may work but has not tested it. The bootable 1.5 MB ROM disk requires 2 MB of flash and a correctly prepared image.

Adds bootable CompactFlash storage through the PDS, bypassing the original SCSI implementation.

For this system (exact model): The maker explicitly supports the IIfx. This version omits the unused top PDS connector, does not support stacking another PDS card, and must be set to slot ID E.

The maker states that production is on hold with no ETA. The public support repository contains firmware and installation files, but no DIY hardware fabrication package.

Connects modern USB HID keyboards and mice to Macintosh computers through Apple Desktop Bus.

For this system (bus/interface): The IIfx provides Apple Desktop Bus for its keyboard and mouse, and Rabbit Hole specifies QuokkADB for any ADB-equipped Macintosh.

HIDHopper Base, Base with USB Hub Hat, and Hub Hat-only selections could be added to the JCM cart on 2026-07-24. The assembled QuokkADB Rev. 2022g remained sold out, while its Raspberry Pi Pico Community Edition remained buildable. HIDHopper's Hub Hat requires external USB-C power, must be power-cycled between Macintosh starts, and can otherwise exceed the host's ADB power budget.

Provides a programmable 2 MB Macintosh ROM SIMM using four socketed PLCC32 flash chips.

For this system (exact model): The IIfx is explicitly named. Confirm that the chosen ROM image supports the exact hardware and software configuration.

The current page offered populated and chipless versions in multiple PCB colors on 2026-07-24. Its dated notice says the red PCB alone was out of stock on 2026-04-26, with black and purple also listed.

Open-firmware SCSI emulators in DB-25, internal 50-pin, laptop, and Wide SCSI form factors.

For this system (bus/interface): The product is designed for direct attachment to any DB25 SCSI host, and the IIfx provides external DB25 SCSI. A Pico Slim must be the final device because its termination cannot be disabled; use USB power if the SCSI chain does not supply termination power.

Rabbit Hole Computing offered current Compact RP2040, Blaster, and Wide variants on 2026-07-24. A 2026-07-27 follow-up found its mostly assembled $25 Pico Slim V1.3 PCB kit sold out, while SamplerZone exposed an Add to Cart path for a $79.95 assembled and cased Pico Slim with configured microSD media. Rabbit Hole's direct Pico2 Slim and Laptop Blaster pages were also sold out. TinySCSI was archived in January 2025, but its V1.0 and V2.0 KiCad files remain available for personal builds. A project discussion documents Wi-Fi DaynaPORT operation on a Pico Slim under System 7.5.5 with the DaynaPORT SCSI-port driver, but does not establish a minimum System version or equivalent networking support for every family variant. Connector, termination, power, speed, and initiator support vary by hardware.