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Mac ROM-inator I kit for Mac Plus, Mac 512K / 128K

Standard Kit: 36USD(All necessary parts are included, only tools are required)

Luxury Kit: 54USD( Standared kit and 2 sets of ROM)

Feb 27th 2024: Some of the PCB designs have been updated.

-Made the MacPlus and Mac512K (128K) selectors with solder jumpers. Soldering has become easier.

-Reduced the ground surface of the GND pad of 74HC02. This improves heat conduction and makes soldering easier.

-Silkscreen changes
-Other specifications respect Steve Chamberlin and remain his design.


We are now selling the ROM-inator I kit, designed by Steve Chamberlin at BMOW, used with permission. BMOW's product page is here:



1, ROM 1 for Mac Plus or Mac 512K, with pre-installed System 6.0.8 ROM disk created by BMOW

2, ROM 2 for Mac 128K, with pre-installed System 3.2 ROM disk, Software compatible with Mac 128K is installed.


Standard kit includes:

Adapter PCB, Pre-flashed ROM x2 (HI and LO), 74HTC02 Gate IC, IC pin sockets x4, custom low-profile pin-header x4, 4-pin pin-header and jumper cable for CPU.


Luxury kit includes:

Standard kit with an extra set of additional ROMs in case the program fails with the Tool software.


What to prepare yourself:

Tools (good soldering iron, solder, flux, nippers and tweezers etc)


This Mac ROM-inator I Original kit has the following functions other than being a replacement part for a failed ROM.


・Replace the startup sound

・Change the Happy Mac icon

・Bootable ROM disk *you can edit

・Native HD20 support *You can use BMOW floppy Emu in HD20 emulation mode w/out real HD20.

・Tweak the ROM code behavior


If the IC soldering work is successful, the work will be easy to finish. Booting with a ROM disk can be done instantly, so it's really impressive! Very useful for Mac 128K and 512K without SCSI.

With the ROM FLASH TOOL provided by Steve, you can reprogram the ROM-inator directly on a Mac. * No need for EPROM programmers.

The main benefits of reprogramming are to change the boot chime and Happy Mac icon, and install your own edited boot ROM disk.


Note: The ROM FLASH TOOL cannot be used by the Mac 128K because the software does not supports 128K memory.  If you are considering upgrading to 512K, you will need to replace 16 onboard RAMs. Next, by installing our device Fat Mac Switcher, you can switch between 128K and 512K! 


Currently, the Youtube video by James Wages is the most straightforward explanation, and we recommend watching it before making the kit.

Click here for assembly instructions:


You can download the required program here.

Rom Flash Tool

Flash Tool Data


Note: The ROMs (HI and LO) included in the kit have been pre-flashed before shipping. Basically, if you assemble it, it will work. If new EEPROM is difficult to obtain, refabricated chips are used. *Inspected and cleaned in Japan.

ROM-inator Resurrections

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