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Mac ROM-inator II

Mac ROM-inator II rominatorii-front-and-back

Want to add new features to your old Mac? The Mac ROM-inator II replaces the stock Macintosh ROM SIMM with a custom flash memory module. Add a bootable ROM disk, make your system 32-bit clean, gain HD20 hard disk support, and more. The Mac ROM-inator II supports the Macintosh SE/30, IIx, IIcx, IIci, IIfx, and IIsi.

The Mac ROM-inator II is fully assembled and ready to use. Just plug it in and go.

rominator-ii  Mac ROM-inator II Atom, $45
2 MB SIMM pre-programmed with ROM Disk with System 7.1, HDSC Setup, ResEdit, and SCSI Probe. Compatible with Mac SE/30, IIx, IIcx, IIci, IIfx, IIsi.
More Info

  Find more items in the BMOW store

The Mac ROM-inator II is great for breathing new life into your old SE/30 or II-series Macintosh. The ROM disk provides fast and convenient boot-ups and a collection of disk utility programs, and customized startup sounds and icons add a touch of fun. The ROM SIMM comes pre-programmed with a BMOW-made custom ROM containing the following changes:

  • ROM disk provides a diskless booting option
  • HD20 hard disk support built-in
  • 32-bit clean – allows use of System 7.6+ and more than 8MB RAM
  • Memory test is disabled for faster booting on 16MB+ systems
  • Customized startup chime – major 9th arpeggio
  • Happy Mac icon is replaced by a color smiling “pirate” Mac
  • New startup menu screen displays installed RAM, addressing mode, and ROM disk details

The ROM-inator II is based on Doug Brown’s earlier Mac ROM SIMM design, used with permission.



ROM-inator II instruction manual: PDF

BMOW ROM SIMM Programmer 3D-printable case: simm programmer case




The ROM SIMM and pre-programmed ROM contents are compatible with the Macintosh SE/30, IIx, IIcx, IIci, IIfx, and IIsi. The SIMM simply snaps into the ROM socket on the computer’s logic board. Note the Macintosh SE differs from the SE/30 internally, and is not compatible with the ROM-inator II.

CPU accelerators such as the Daystar PowerCache and Turbo series are not compatible with the ROM-inator II.

Some SE/30 hardware may require a shim to ensure ideal fit of the SIMM – see instructions for details.

If running Mac OS System 7.5 or later, some Mac models require a software patch to the System file.


HD20 Hard Disk Support – The pre-programmed ROM includes support for HD20-type hard disks, such as the hard disk emulation mode of the BMOW Floppy Emu disk emulator. The stock ROMs in the Macintosh SE/30, IIx, IIcx, and IIfx lack HD20 support, so these computers are normally unable to use HD20 disks. With the ROM-inator II, HD20 support is built-in.

32-Bit Clean – The pre-programmed ROM also makes the Mac 32-bit clean, enabling it to use more than 8 MB of RAM natively without the need for special system enablers or extensions, and to run newer versions of System software that require 32-bit clean ROMs. Some older Macintosh models like the SE/30, IIx, and IIcx have stock ROMs that are “dirty”, meaning they can’t support 32-bit addressing without ROM patches. Using the Mac ROM-inator II and the pre-programmed ROM, the Mac SE/30 can support up to 128MB of RAM!

Faster Startup – The power-on RAM test is disabled in the pre-programmed ROM. This speeds up boot times on Macs with 16 MB or more of RAM, skipping a time-consuming check that can take up to 1 minute otherwise.

ROM Disk

With the ROM-inator II, you have the option to boot normally from a standard startup disk, or to boot from the built-in ROM disk. The included ROM disk is like a recovery partition for your Macintosh, containing System 7.1 and a collection of disk utility programs. With the ROM disk it’s possible to boot a computer with an unformatted or damaged hard disk, and then format or repair it using the utility programs. Or boot a computer with no physical disks at all, to perform troubleshooting and diagnostics.

The ROM disk contents are stored compressed, and are decompressed on the fly as needed, in order to squeeze the largest possible disk image into the available space. This requires 1MB of RAM for caching of decompressed disk sectors, so a minimum of 2MB total system RAM is required. The ROM disk can be mounted as read-only, or as a read-write RAM disk.

The ROM disk contains:

  • System 7.1, with System Update 3.0 and Apple CD-ROM Extension 5.3.1
  • HD SC Setup 7.3.5 (patched to support formatting non-Apple hard disks)
  • SCSI Probe 3.3 (for troubleshooting the SCSI bus)
  • ResEdit 2.1.3


Most of the ROM-inator II’s benefits are automatic: just install the SIMM, and you’ll gain HD20 support, 32-bit cleanliness, and custom sounds and icons. Only the ROM disk requires any user interaction.

When first powered on, a Macintosh with the ROM-inator II will play a customized startup sound, and display diagnostic info about the amount of installed RAM, the current addressing mode, and the detected ROM disk type. After a moment, an interactive startup menu will be displayed.

To boot from the ROM disk as a read-only disk, press the R key on the keyboard. Or to convert the ROM disk into a writable RAM disk, press the A key. Or to bypass the ROM disk, do nothing and wait five seconds. If no keys are pressed, the Macintosh will boot normally from an attached SCSI or HD20 disk, or wait for a floppy disk to be inserted.

Note: If booting from a SCSI disk when the ROM-inator II is installed, any 32-bit enablers or extensions such as MODE32 or 32-Bit System Enabler must be removed from the disk’s System folder.

romdrv-splash2 romdrv-splash


For advanced users with external SIMM programming hardware, the Mac ROM-inator II’s contents can be reprogrammed, providing the ultimate in customization. Edit the ROM disk image, change the ROM code, or try other crazy experiments. Go nuts! More information is available on the ROM-inator II Programming Page.

Get One Now

Check out the Mac ROM-inator II at the BMOW Store.


139 Comments so far

  1. ResEdit - May 25th, 2016 9:13 pm

    Awesome stuff. If Apple did this back in the day, it would really blow away the competition.

  2. Kristian Möller - May 30th, 2016 2:46 am

    Now I want a Mac II! If I where to invest in II or IIx (IIci is so damn hard to find) what graphics card should I use?


  3. AEChadwick - June 19th, 2016 6:20 pm

    Hey Steve, i love your tireless work and have bought several of your products. Have you improved or streamlined Doug’s design? or are you simply the caretaker in this case, keeping the work alive? (to be clear: i have one of Doug’s ROM Simm cards and the programmer… but, you know, just give me an excuse to buy another…!!)

  4. Steve - June 19th, 2016 7:42 pm

    Both the SIMM and the programmer have changed from Doug Brown’s earlier designs, and the SIMM also now comes pre-programmed, with the on-the-fly compression disk driver that I designed. The new programmer is about 4x faster and also has an on/off switch and power LED. And it’s hexagonal. 🙂 The new programmer also works with Doug’s old SIMMs, and the old programmer will work with the new SIMMs if you update the software.

  5. Brian Holdsworth - June 23rd, 2016 10:10 am

    Hi Steve. Based on your comments above, the new is backwards compatible with the original dbrown SIMM and Programmer, right?

    This is great news. I was running into the limit with the 8MB ROM in my IIsi and want to try out the new compression driver to see what more I can fit in there 🙂

    Once I get the SE/30, I’ll add another one for that machine, because the boot speed, silent operations, and convenience are awesome.


  6. Ben - July 5th, 2016 7:18 am

    Hi Steve, Mac ROM-inator II is out of stock. It will available soon ? :'(

  7. Steve - July 5th, 2016 8:05 am

    I’m awaiting delivery of more parts, and hope to have new stock ready in a few weeks.

  8. Ben - July 5th, 2016 9:08 am

    Oh It’s a good news. Thx. 😉

  9. Steve - July 11th, 2016 10:03 am

    The ROM-inator II SIMM is back in stock.

  10. Alden - August 11th, 2016 10:26 am

    Would the base ROM the SIMM comes with be compatible in a IIci with a Daystar Turbo 040 PDS accelerator?

  11. Steve - August 11th, 2016 3:28 pm

    Probably not. I believe the Daystar accelerator has its own ROM and does some kind of run-time ROM patching. If you try it, let me know what you find!

  12. Dan Perry - August 20th, 2016 11:08 am

    I just got my Mac Rom-inator II in the mail and installed it in my SE/30!
    Having HD20 support plus native 32-bit clean is great! It as well boots much quicker.

    I am likely going to be purchasing the programmer in the near future as it would be awesome to have my OS boot directly from RAM, freeing up some space on my (miniscule) 40mb HDD.

    Thanks Steve!

  13. Todd Killingsworth - November 16th, 2016 7:05 pm

    I’ve finally gotten my SE/30 recapped, and put everything back together. Good news: It all works first time…. Bad news: When I replace my original ROM with the Rom-inator II, it only works when I disconnect the floppy drive. I read the manual PDF, but I didn’t see anything specific to this issue. I’ve got a new fully matched set of RAM from OWC, so I don’t think that’s the trouble. As an SE/30, there shouldn’t be a jumper to change. I’m at a loss here…. any suggestions?

    Thanks for any insight you can give!

  14. Steve - November 17th, 2016 7:17 am

    Hmm, that’s strange. Have you tried pushing on the ROM SIMM while it’s booting, or using a shim, as described in the manual? Some SE/30’s seem especially picky about the ROM SIMM. If you’re unable to get it to work in your machine, you can return it for a refund, but hopefully it doesn’t come to that.

  15. Roland - December 9th, 2016 11:49 am

    Dear Steve,

    today I received 2 Rominator II sets. I installed them in a IIfx and a SE/30 – everything worked fine immediately ! A wonderful piece of soft- and hardware !!!

    I had minor problems programming them: Mac OS Sierra was not able to communicate with the programmer (the window with progress bar saying “starting communication ,,,” stayed forever). But maybe that is an issue due to my patched Sierra on an unsupported Mac. Using Mac OS ElCapitan everything went well.

    In Windows 10 your software complains about a missing plug-in “QT windows” and refuses to work.


  16. Alden - December 13th, 2016 9:15 am

    Roland: I too have the “Staring Communication…” message in macOS 10.12.1 Sierra, but found quitting the app, then reading the ROM to a file is successful, THEN you can write to the ROMinator successfully. Annoying, but does end up working!

    Steve: Not sure if anyone has customized the iisi+romdrv1.2.rom file for a Daystar Turbo 040, but I’d be interested – currently no boot chime if used with Turbo 040 installed.

  17. Steve - December 13th, 2016 1:54 pm

    Thanks for the macOS Sierra software work-around. I’m interested to hear if others have the same experience. As for the Daystar 040 accelerator, I believe it has its own on-board ROM, which tries to patch sections of the main ROM. Those patching attempts probably go horribly wrong when using a non-stock main ROM like ROM-inator II.

  18. Christopher Parish - January 3rd, 2017 2:38 pm

    This is a super useful tool for some hardware development I’m doing with the SE/30. Two quick things:
    1. The programmer doesn’t run out-of-the-box on Windows 10. I just rebuilt it in Linux (where I normally work), but others may have the same issue.
    2. Do you have a listing of the offsets where the startup sound, boot icon, etc. live like the ROM-inator v1?

  19. Christopher Parish - January 3rd, 2017 4:00 pm

    Well, that’s what I get for not reading everything. With the IIsi specific formatting information and FDisasm (, it looks like the icon starts at 0x17F2 and the chimes are all synthesized with the data tables at 0x7158.

  20. Steve - January 3rd, 2017 6:37 pm

    Thanks for the note on Windows 10. I don’t have a Win 10 system for development at the moment – looks like I’ll need to get one. I suspect the issue is with the 3rd-party library used to enumerate and talk to the USB.

  21. Huxley Dunsany - January 4th, 2017 10:06 pm

    So I just received my shiny new “Mac ROM-inator II” ROM stick and I’ve popped it into my SE/30. I’m able to boot from the Mac ROM-inator II’s bootable ROM/RAM disk without issue and everything seems totally normal, but when I attempt to boot to MacOS 7.5.5 from my internal SCSI drive, the system hangs at the “Welcome to Macintosh” screen. I double-checked that I don’t have Mode32 (or any other 32-bits-related control panels or extensions) enabled, and I get the same result if I hold shift down – it shows that it’s booting with extensions disabled, but still hangs at the Welcome to Macintosh screen.

    Any clues here? I’ll try the obvious / easy stuff (reseat my RAM, etc.), but it just seems pretty odd to me. I’ll also try reseating / shimming the ROM stick, but given that it’s able to boot from the ROM / RAM disk, I have to assume that’s not the main issue. Thanks for any suggestions!

    PS I have 64 megs of brand-new RAM arriving from OtherWorldComputing in a few days, so if this indicates a RAM issue, that will probably sort itself out shortly…

  22. Huxley Dunsany - January 4th, 2017 10:51 pm

    Nevermind – I’m a dummy and I neglected to RTFM. I’ve followed the guide and made the appropriate ResEdit tweak to my MacOS 7.5.5 System file, and the SE/30 is humming along as expected now. Whew!

  23. Kristian Möller - January 5th, 2017 1:15 am

    What tweak? I have the same issue! With my MacIIcx (7.5.3)

  24. Huxley Dunsany - January 5th, 2017 6:14 am

    Kristian – I was referring to the ResEdit guide posted here:

    Since I have MacOS 7.5.5 on the internal drive of my SE/30, I followed that guide, changed a “0003” to a “0005” in one particular value of the system file, and the whole issue was fixed immediately. Given that this is necessary, I wish ResEdit could be included in the bootable OS found on the ROM stick – would’ve saved me some time having to shuttle ResEdit via floppy from another Mac!

  25. Kristian Möller - January 5th, 2017 3:20 pm

    Thank you for the link Huxley.

  26. Roland - January 13th, 2017 12:09 pm

    I have 2 Rominator II, one for a SE/30, the other for a IIfx. Additionally I use the floppy emu, which is working fine with the SE/30 on the external port.
    On the fx (without external Floppy-port) I plugged the floppy disk emu directly to the floppy-ports on the mainboard. Unfortunately the IIfx does not recognize the emulated HD20 (as the SE/30 did). Independent, which floppy-port I use on the IIfx.
    Any ideas how to solve the problem ??

  27. Steve - January 13th, 2017 12:38 pm

    Sorry, I wasn’t aware the IIfx lacks an external floppy port. The Apple HD20 ROM routines are designed to expect the hard drive on the second (external) floppy port only. Since the IIfx has two internal floppy ports on its internal logic board, you may have success if you try connecting the cable to the other port.

  28. Roland - January 13th, 2017 2:37 pm

    unfortunately the floppy-emu is not recognized independent which port I use 🙁

  29. Roland - January 13th, 2017 2:38 pm

    .. both ports are working well with the original floppy

  30. Roland - January 13th, 2017 2:51 pm

    the IIfx has a 6502 CPU subsystem to handle the floppy ports – may this cause the problem ?

  31. Steve - January 13th, 2017 3:34 pm

    That sounds plausible. If the IIfx’s connection to the floppy ports works substantially differently than in other supported Mac models, then it’s likely Apple’s HD20 routines in the ROM-inator II ROM code won’t know how to handle it.

  32. Steve - January 13th, 2017 5:52 pm

    For those having problems under Windows 10 with the ROM SIMM programmer utility software, try downloading the newest version of the software from the link above. The older version was missing some required DLLs. I’ve also left the link to the old version in place for the time being, just in case the new one has any unexpected problems.

  33. John A - January 14th, 2017 6:46 pm

    Great ROM!!!

    As others had stated before, my SE/30 would freeze at “Welcome to Macintosh” with OS 7.5.5…

    To fix this, simply go over to the guide with the resedit tweaks, and follow the instructions for OS 7.5.5, and change that value of 0003 or something like that (It says in the guide) to the 0005. Worked great for me!

    One problem I had was that when I booted to a ram disk, I keep getting disk unreadable. However, that was before I edited the file…

  34. Patrik - March 20th, 2017 3:40 am

    I have just bought ROM-inator II to my SE30 but can not get it to work.
    With the standard ROM the se30 works but with the ROM-inator II it get zebra stripes.
    I have try different RAM configurations but no differance, only zebra lines.

    Any help appreciated 🙂

  35. Steve - March 20th, 2017 6:40 am

    Try one of the methods described in the manual for bracing or shimming the SIMM in the SE/30 ROM socket. You can email me directly if you need additional help – the address is on the Contact page.

  36. Denny Atkinson - April 12th, 2017 1:18 pm

    Maybe I’m missing a step. I just installed ROM-inator II on my 32 meg SE-30 (8, 4 meg simms). It boots into 7.1 from the ROM disc, but when I get info About This Macintosh, it shows Total Memory of 32,768K, Largest Unused Block of 6,934K, and the System Software using 25,808K. If I remember correctly (thinking back 25 years or so), that’s what happens without Mode 32 installed. Isn’t the ROM-inator supposed to be addressing that or am I just misunderstanding something?

    I’ve got a Floppy-Emu here and a plan to make a bootable HD20ish setup, but I want to make sure I’m not going to be running into any ROM compatibility issues.

    I’d appreciate any suggestions you can offer.

  37. Denny Atkinson - April 12th, 2017 1:39 pm

    Never mind.

    I forgot that I had to turn on 32 bit addressing in the the memory control panel. It\’s been a long time…cut me some slack. Thanks!

  38. Markus Wagner - April 29th, 2017 2:55 am

    I would like to have one but unfortunately there is no more. It should be back to buy please infomer

  39. Steve - April 30th, 2017 8:25 pm

    Please check back in a few days; I should have more ready for sale.

  40. Tristan Woodrich - June 21st, 2017 3:19 pm

    Is it possible to do a similar upgrade for power mac systems?

  41. Steve - June 21st, 2017 3:25 pm

    For certain values of “possible”, yes. 🙂 Some PowerMacs have their ROM on a removable module, so in theory you could replace it with something custom. But the hardware and software would be entirely different from the ROM-inator II.

  42. James Wages - July 16th, 2017 10:24 pm

    When will the MEGA be back in stock?

  43. Steve - July 17th, 2017 6:09 am

    Should be a few more days.

  44. Steve - July 20th, 2017 10:53 am

    More MEGAs are now available.

  45. Kristian Möller - September 29th, 2017 7:53 am

    So, I have now done some tests with the ROM-inator II and two Daystar PDS accelerators, one 33MHz 030 and one 33MHz 040 Turbo in an IIcx with an original Daystar adapter. The 030 works like a charm, but the 040 only gives death tones. Whats the difference? Since the 040 is suppose to work in an IIsi?


  46. Steve - September 29th, 2017 11:57 am

    See some of the comments above about the DayStar accelerator. I believe it has its own on-board ROM, which tries to patch sections of the main ROM.

  47. Samuel Clements - February 11th, 2018 7:36 am

    Hi! Any chance the 32 bit clean ROMs here will allow an otherwise unmodified SE/30 run A/UX 3.11 reliably?

  48. Steve - February 11th, 2018 7:49 am

    I don’t have any experience with A/UX, so I’m not sure.

  49. Bunsen - February 12th, 2018 2:17 am

    Is there a listing available of what comes pre-installed on the ROM-inator-II / Mega?

  50. Steve - February 12th, 2018 7:04 am

    The pre-programmed MEGA disk image is in the downloads section (the blue box above): romdisk-mega.dsk. You can open it with you favorite Mac emulator or Floppy Emu if you want to check it out.

  51. Jeff - April 6th, 2018 6:13 am

    Hey, just wanted to provide some info on the ROMinator II MEGA with a Daystar PowerCache 33Mhz in an SE/30.

    Mine works fine IF the RAM is a matched set.

    Some things to mention that may indicate the accelerator is not the cause here:

    1. I don\’t have a stock 68K for the SE/30 to test without the accelerator.
    2. I don\’t have a stock IIsi ROM to test against the Rominator.

    So, grain of salt I guess, but matching RAM seems to be a must.

  52. Steve - April 6th, 2018 6:45 am

    I think it’s only the 040-based TurboCache accelerators that don’t work, but I’m not certain.

  53. Jeff - April 6th, 2018 8:58 am

    It may just be that the IIsi ROM is picky about the RAM.

  54. Paul - May 1st, 2018 12:21 pm

    As info, (and as pointed out by Steve and others in previous comments), the Daystar Turbo040 patches sections of ROM in memory and it won’t boot using a stock 32-bit clean image.

    However, I got a custom ROM with the 040 driver built in and do have my SE/30 running Mac OS 8.1 smoothly with a 33 MHz Turbo040. I tested the image out on both 4 MB and 8 MB MEGA SIMMs and works great.

    I lack any assembly skills whatsoever so I did give up the ROM disk and I’ve not had success with getting that grafted on. But have hope! You can search the 68kMLA forums for my thread (and give credit to another user that shared it with me)

  55. James Wages - May 1st, 2018 6:48 pm

    Paul, I can’t find the 68kMLA thread you spoke of. Please use Bitly to create a short URL to it and post that. If URLs are filtered here, then please type the BItly URL out in a way it won’t be filtered. Thanks.

  56. Paul - May 2nd, 2018 5:34 am

    James – no problem, here it is:

    Again, I can’t take credit for the actual ROM (as I believe another user got it custom from Doug) but sharing in the hopes someone can either a) adapt for the Turbo 601 (of which I have two) or b) add the ROM disk, which isn’t as simple as concatenating the two ROM sections.

  57. James Wages - May 2nd, 2018 3:31 pm

    Paul, thank you for the link. I just posted a reply in that thread. I am JDW.

  58. Steve - May 2nd, 2018 4:16 pm

    Awesome, thanks for sharing!

  59. James Wages - May 2nd, 2018 4:42 pm

    Hi, Steve. I’m currently mulling a purchase of a ROMinator II MEGA and programmer, and a FloppyEMU Bundle. Any forthcoming “Spring 2018 Discount Codes”? 🙂

  60. Steve - May 2nd, 2018 4:48 pm

    I just had a sale on the ROM-inator MEGA that ended a couple of days ago, and the ROM-inator programmer is on sale now. That’s all for discounts at present.

  61. Paul - May 2nd, 2018 4:56 pm

    Hi James,

    I shared the link to the ROM in that post/comment. I’ll PM you over there.

    Steve – thanks for letting me share that link and for two awesome products. If you have any advice to share in getting the bootable disk .img appended to that 040+ROM file, I’m all ears.

  62. James Wages - May 2nd, 2018 5:02 pm

    Thank you for your kind reply, Steve!

    By the way, if you’re thinking of new products that would benefit the vintage Mac community, especially those of us who own and love the SE/30, I would love to see a replacement PSU product become available at a price point lower than what ARTMIX Japan charges. They want US$200 plus shipping for their model that was last revised in 2009. And it’s not clear if their inventory is old stock from 2009 or something made in the last year either. I say this because I recently had a power supply die, just last night in fact, in one of my SE/30s.

    Anyway, thank you for the great gadgets and for your enthusiasm in putting them out there for us to buy. I really appreciate it.

  63. James Wages - May 2nd, 2018 7:21 pm

    Steve, please forgive me but there\’s \”one more thing.\” 🙂

    I\’ve read through the ROM-inator II PDF User Manual and Tutorial, but there is no mention of \”*.bin\” files. The issue that Paul and I are trying to make sense of centers on *.bin files. For detailed information about this, please see my latest post (JDW) on the 68kMLA by clicking on the thread Paul kindly linked for us above. In that post, I (JDW) explain everything very clearly. Any answers you could kindly provide would be greatly appreciated.

    Lastly, please be gentle as I\’ve not even pulled the trigger yet on my first ROM-inator II purchase. I have them sitting in my Cart though and am now just trying to gain clarity on what\’s feasible with the technology so as to make good use of my forthcoming purchase.

    Many thanks.

  64. Steve - May 2nd, 2018 8:45 pm

    *.bin just means a binary file, but isn’t very descriptive, and I don’t use that suffix for any of the ROM-inator data files. From the context, it sounds like this *.bin file is a new base ROM image specific to the Turbo040 accelerator. I’m not sure how that was created, or whether it supports a ROM disk, or whose ROM disk driver and format it supports. You could try concatenating romdisk-standard.dsk from the Downloads section above, program it to your ROM SIMM, and see if it works. If not, then your custom Turbo040 base ROM probably does not include ROM disk support.

  65. Joshua Brooks - September 9th, 2018 7:53 pm

    This will work with a plain Macintosh II correct? I’m getting back to the Mac scene and I want to make sure it’s compatible with it. I assume it is since it’s in the same series but I’m not sure

  66. Steve - September 10th, 2018 6:47 am

    Sorry, the original Macintosh II is not compatible. The list of compatible computers is shown in the hardware description at the top of the ROM-inator II page.

  67. Dan - November 12th, 2018 1:42 pm

    I’ve been interested in a ROM-inator II for my SE/30 since I fixed it, however, I wondered if I could custom order one preprogrammed with the original SE/30 boot sound and original Happy Mac icon instead of the Pirate Mac. I’m perfectly fine with the rest of the stock ROM-inator contents, so paying an additional $59 + all of the import duties to go with it for a programmer I’d likely use once, makes little sense. I’d be prepared to pay a bit extra for the customization, of course. I’d just like to keep those two small things stock.

  68. Steve - November 12th, 2018 5:41 pm

    Sorry, but the ROM-inator SIMMs are manufactured with the BMOW image and I can’t do customized one-offs. You may be able to find another ROM-inator owner who can assist you if you don’t want the programmer.

  69. James Wages - November 12th, 2018 5:46 pm

    Dan, I was faced with the same issue. And while other ROM-inator owner’s are willing to help, it doesn’t financially make sense. I live in Japan, and most of the willing ROM-inator owners don’t. Am I really going to ship to them and pay for them to ship back to me? Of course not. So I ended up buying a ROM-inator so I could do that one-time programming. In fact, I’ve not even done that yet. But it’s nice that I have the ROM-inator just in case.

  70. Miles Raymond - January 30th, 2019 11:33 pm

    Any idea when the MEGA+programmer will be back in stock for purchase?

  71. Steve - January 31st, 2019 7:18 am

    They won’t be, sorry. The 5 volt flash memory that the ROM-inator SIMM needs was discontinued by Toshiba.

  72. Steve - March 28th, 2019 10:53 am

    The 64-pin sockets for the SIMM programmer are no longer commonly available, nor are the 5V flash chips for the SIMM. But even before obsolete parts forced a halt to ROM-inator II sales, the business case for it was weak. I was never really able to sell enough of them to make all the time and hassle worthwhile. It was a very high-touch product, with many of the sales leading to marathon-length tech support discussions. Not every electronic gizmo makes a good business. So I couldn’t justify the R&D needed to make a new SIMM design now with a new set of hardware. If a low-capacity Macronix part could just drop-in to the existing SIMM PCB, perhaps a non-programmable 512KB SIMM would be feasible and low effort for me. That would at least give SE/30 owners a path to a 32-bit clean ROM with HD20 support, which was the most common use for the ROM SIMM.

  73. CharonPDX - April 30th, 2019 4:34 pm

    Dang it! I have a ROMinator II (great product, by the way!) but I kept meaning to get a programmer so I could change the ROM Disk image, and never got around to it. Any chance of any sitting around left to sell?

  74. Sean - May 7th, 2019 3:53 am

    I have a ROM-inator II and I have made myself a System 6 image with Civ, Tetris and Prince of Persia on it.

    Can you help me with networking by default?

    I assembled the image in mini vMac 26 (the MacII flavour) and I can’t get AppleTalk active by default, MacTCP 2.0.6 doesn’t see the EtherTalk extension and the Network CDEV won’t start because AppleTalk is inactive.

    When my IIfx boots up, the EtherTalk extension is visible, but I can’t change anything because it is read-only. As a workaround, I’m having the System Folder transferred to a RAM disk on start-up and that will allow me to configure it manually. However, I’d rather not have to do it on each cold start. Do you have any ideas to make my image network ready on startup?

    Thanks very much,

  75. Brian H - May 7th, 2019 7:03 am


    I did something similar on my IIsi. The EtherTalk extension and AppleTalk are active at boot up because:

    1. I set it up to run from RAM, not the ROM. Plenty of RAM on my IIsi.
    2. My PRAM seems to correctly recall my AppleTalk settings on boot. Do you have a good battery in your IIfx?

    However, I’m not using MacTCP and I am using System 7.

  76. Sean - May 8th, 2019 1:22 am

    Hi Brian

    It’s funny that you should mention batteries (the IIfx needs 2), I had been thinking about them as a source for my woes. I shall check them. I may yet have to boot from System 7 and sacrifice a game.


  77. Steven - July 3rd, 2019 4:39 pm

    Has anyone tried soldering a SIMM socket onto a Macintosh IIvx logic board? The header is there, but no socket. I’d love to test this ROM in my machine!

  78. Miles Raymond - July 8th, 2019 9:28 am

    If anyone has an 8MB and programmer, I would very much appreciate purchasing them. I would like to experiment with the boot code and creating a better ROM image.

  79. bernardo jimenez - July 29th, 2019 8:39 am

    Hi, I got an IIcx, which i know the ROM-inator works on (so I would like to order one) and also a IIc, but that one is not supported, is it? is there any way to connect the Rominator to it externaly, or something?

  80. Brian H - July 29th, 2019 3:55 pm

    Hi Bernardo.

    There is a Mac Iix, a Mac Iicx, and a Mac IIci. There was ever a “Mac Iic”.

    If you are actually talking about an Apple Iic, that’s incompatible with the Macintosh line. It’s part of the Apple II family.

  81. bernardo jimenez - July 30th, 2019 4:03 am

    Yes Brian, you are right, sorry messed things up. I meant that I have an apple IIc and a Macintosh IIcx.

  82. Brian H - July 30th, 2019 8:11 am


    No worries but you should also check out the Floppy Emu for sale on this site (though currently out-of-stock). It will work as a disk drive replacement for both your computers to allow loading software from an SD card.


  83. bernardo jimenez - July 30th, 2019 8:21 am

    Yes Brian, it´s my intention to get both the Floppy EMu and the ROM inator. Hope I´ll be able to do it soon (our weak currency, here in Colombia, makes everything more difficult, but I´ll make it for sure)

  84. Brian H - July 30th, 2019 8:30 am


    Congrats on your nation’s Tour de France success!

  85. bernardo jimenez - July 30th, 2019 8:33 am

    Thank You! Everyone here is going nuts with that…It was very emotional for everyone here…

  86. Miles Raymond - October 13th, 2019 6:14 pm

    Hi Steve, since I don\’t have access to a programmer, if I purchase one of the Atom SIMMs from you, could you pre-program it with my second System 8 ROM image from this MacRumors post?

    Of if you have one last 4MB or 8MB version left for me… 😀

  87. Steve - October 13th, 2019 8:32 pm

    I made an intentional choice with the ROM-inator II Atom to offer one specific and thoroughly-tested BMOW ROM image, which is described here. If you wanted to make a custom ROM, you would need to do the modifications/reprogramming on your own.

  88. James Wages - October 14th, 2019 1:38 am

    Miles, the Atom is only 2MB so Steve’s decision to use System 7.1 on the included ROM disk is sound. That System is the fastest version of System 7 and maximizes software compatibility. But the ROMinator II Atom is still useful even if you don’t use the ROM disk because it’s 32-bit clean, eliminates cold boot RAM checks, and offers HD20 compatibility which I love when using my FloppyEMU because I can create a big disk on my FloppyEMU and boot my SE/30 from it because I have the ROMinator II. Without the ROMinator II, I could only use my FloppyEMU for floppy disk sized disks. But with HD20 compatibility in ROM, I can make a 200MB or larger “floppy” that is bootable and contains a lot of software. The only down side is the FloppyEMU runs at the speed of the floppy serial interface. If you really want fast though, you would need a SCSI2SD solution.

  89. Miles Raymond - October 16th, 2019 11:13 am

    As already stated, I don’t have access to a SIMM programmer, so I can’t reprogram my own, and I haven’t found anywhere else to purchase one. I already own a 2M version so I already enjoy the other benefits – 32bit native, no RAM check, HD20 support. I also bought the full FloppyEmu package to make use of that HD20 support!

    My specific use case is a ‘recovery’ environment in the ROM that fits my use case. Ideally I’d like an 8.1 recovery for accessing HFS+, but I haven’t gotten it able to fit in ~2M image yet, which is all that is available, and all that I have to work with right now.

  90. Samuel Clements - November 9th, 2019 7:26 pm

    For the record, I took an SE/30 that was running A/UX and had 128M of RAM (but could only address 24 bits worth) and installed a ROM. I was then able to boot A/UX cleanly and address all 128M after modifying the available memory in the Memory Control Panel! I’m still having issues installing with the ROM installed, but it seems to install okay with the stock ROM, then swapping after the install completes cleanly. This is a fantastic product, thank you!!

  91. Dandu - December 15th, 2019 7:34 am


    I have a little problem : i have erased the Mega SIMM for a test, and i have not made a backup from the original pre-programmed ROM (yes, i am dumb)

    Is there a way to download it ?


  92. Steve - December 15th, 2019 8:16 am

    Email me and I can help you out.

  93. Dandu - December 15th, 2019 9:21 am

    Thank you !

  94. Kahlil - December 27th, 2019 1:40 pm

    Which model originally used the major 9th arpeggio chime?

  95. Steve - December 27th, 2019 1:41 pm

    None. It is a custom chime.

  96. DrBunsen - April 28th, 2020 6:15 pm

    Steve – is there any prospect of being able to persuade the Mac to do the programming in system, like with the older ROMinator?
    That’s if and when this project gets rebooted as a new version, of course.

  97. Steve - April 28th, 2020 6:37 pm

    I don’t think so, because for the Mac II series the write-enable signal isn’t physically connected to the ROM socket on the logic board.

  98. DrBunsen - April 28th, 2020 7:32 pm

    I thought that was what the jumper wire in the earlier version was for

  99. Will - May 17th, 2020 5:48 am

    Hi ! is it impossible to use the Rom-Inator with a simple Macintosh SE ?
    Thanks for your help !

  100. Steve - May 17th, 2020 6:39 am

    The regular Mac SE doesn’t use a ROM SIMM, so it’s not compatible. The Mac SE/30 *is* compatible because it’s an entirely different machine – it’s basically a Mac IIx with fewer NuBus slots.

  101. Joe - May 18th, 2020 3:52 pm

    Hi, I’m having a few problems with mine on a IIx.

    The first is that the SIMM seemed to be a bit too thin to fit properly in the slot (so I had to pull it forward before the machine would chime), so I had to add some tape on the back to make it fit.

    The second is that it seems to refuse to boot my System 7.5 Disk Tools disk — it gets to the Welcome to Macintosh screen and hangs. This doesn’t happen with the stock ROM.

    The third is that the Mac only seems to be seeing 4 of my 8 MB of RAM with the ROMinator installed, using either the ROM disk or the copy of 7.1 on the hard drive. Putting back the stock ROM and booting from the hard drive or the 7.5 floppy makes it see the full 8MB of RAM.

    Any ideas on solving these problems? Thanks!

  102. Joe - May 18th, 2020 4:12 pm

    Never mind — the missing RAM issue seems to have gone away on its own, and I found the page on patching the System 7.5 System file.

  103. Krishna - August 16th, 2020 5:42 am

    The ROMinator II initially gave horizontal lines until I went back to the manual and added rubber bands to give the ROMinator extra support. It works great now in my Mac SE/30!

  104. Samuel Clements - August 24th, 2020 12:53 pm

    Just so everyone is aware, Joel build some 3d Printable supports for the ROMinator II. Check it out at:

  105. Michael David Mullett - October 1st, 2020 7:31 pm

    I was Wondering if this would Work in my Outbound Notebook, it uses the ROMs from a Mac Plus or an SE/30?

  106. Steve - October 2nd, 2020 8:02 am

    No, it’s only for specific Macintosh II series machines and the SE/30. The list of supported machines is in the Compatibility section above.

  107. Adam - October 5th, 2020 1:34 pm

    The ROM SIMM arrived but did not boot – made a kind of simasimac pattern. Tape necessary to thicken the SIMM a little, it is thinner than the original. After that with the contacts pressed up against the SIMM slightly harder all is well. Great product!

  108. Joe Altair - October 22nd, 2020 2:58 pm

    So I’m having an odd problem. I’m trying to use the ROMinator II in a IIfx, which works fine. But I’m also trying to run A/UX on the IIfx, which doesn’t work fine — I’m met with a gray screen unless I swap the original ROM back in. The combination of the ROMinator and A/UX works fine on a IIcx or an SE/30. It was suggested over on 68kMLA that this could be because the A/UX startup is applying a different set of ROM patches to the IIcx and SE/30 vs the IIfx, and that some check the startup application is performing on the ROM is getting it confused. Any idea what check it could be performing?

  109. Steve - October 22nd, 2020 3:08 pm

    Sorry, I don’t know. 🙁

  110. Samuel Clements - October 22nd, 2020 3:22 pm

    I was unable to get A/UX to install on am SE/30 with the ROM installed. I was able to install on stock ROMs and then swap after the fact. Have you tried that?

  111. Mike - January 7th, 2021 12:59 pm

    I completely understand if you don’t want to start baking custom ROMs, but is it possible to order a ROM-inator with the stock SE/30 startup chime? It’s half the nostalgia for me 🙂

  112. Steve - January 7th, 2021 7:24 pm

    I only have the one configuration, sorry. If you want something closer to stock, you can use a Mac IIsi ROM in an SE/30.

  113. MichaelLAX - January 24th, 2021 4:21 pm

    Steve: I am enjoying the ROMinator II and Floppy EMU as a 100Mb Hard Drive and I primarily work with System 6.0.8. I have two problems, that I hope you can assist me with:

    I can’t seem to get System 6.0.8 to boot into 32 bit clean mode. Yes, I have removed any Mode32 type INITs, but the ROMinator II opening screen keeps telling me that I am in 24 bit mode. Am I missing something? I tried installing Optima 2.0 and removing all other 3rd party INITs, CDevs, MultiFinder, etc. The ROMinator II opening screen tells me I am in 32 bit mode, but then after the boot process ends, it crashes, telling me that Finder is too old.

    Another problem, maybe related to System 6.0.8 is that I see no difference booting into R or A at startup; both give me a nice 7.1 quick startup, but I do not see any RAM disk. I have 68M of functioning RAM installed properly in my SE/30.

    Lastly, does ROMinator interfere with my ability to turn on AppleTalk in 6.0.8; which I currently cannot turn on?

  114. Steve - January 24th, 2021 5:52 pm

    I think System 6 doesn’t support 32-bit mode.

    Pressing “A” doesn’t create a separate RAM disk, but it makes the ROM disk temporarily writable. Please refer to the instruction manual for details.

    AppleTalk may try to change a system preferences file when you enable it, in which case it won’t work if you boot from the ROM disk. It should work if you boot from another disk, and should work temporarily if you use the “A” booting option, but will get reset the next time you reboot.

    Please use the “customer support” link if you have additional support questions.

  115. MichaelLAX - January 26th, 2021 10:05 am

    It turns out that System 6 does support 32-bit mode, with use of Connectix’ control panel device, Optima 2.0, after its Finder has been easily modified by ResEdit twice to change its version number from 6.1.8 to 6.1.7.

    And better yet, ROMinator II is compatible with such use of Optima 2.0 in System 6. Of course all programs and system extension used in this mode must be 32-bit compatible, eliminating the use of MultiFinder and Program Mgr as examples.

    Thank you for clarifying the difference between “A” and “R” startup modes. I can indeed now make minor changes in “A” mode, but there is not enough room in the System Folder to add the extensions I would like to add. I will just have to install System 7.x into my use of the Floppy EMU’s HD20 mode for which I created a 100 MB hard drive.

    Appletalk is still not working however and I have ordered disk based copies of System 5 and NSI so that I can reinstall it and see if there is still a potential conflict with ROMinator II.

    As suggested, I will ask you additional support questions by email.

    Thank you for a wonderful product that should be acquired by every Mac SE/30 owner!

  116. MichaelLAX - January 26th, 2021 10:07 am

    System 6 and NSI*

  117. MichaelLAX - February 6th, 2021 10:06 am

    Well, the reinstall of System 6 did not get AppleTalk working, but NSI 1.4.5 got it working like a charm! So ROMinator II is indeed compatible.

    My next project is to install System 7.5.3 on the Floppy EMU (with patches), so that using the Farallon iPrint I recently acquired, I can network my Mac SE/30 to my MacMini2,1 with OS X Tiger and leave SneakerNet behind for now.

  118. Tom - April 19th, 2021 5:16 am

    Is there an image file of the Rominator II’s ROM available? I’d like to use it with BasiliskII or SheepShaver to build disk images for my upgraded SE/30.

  119. Steve - April 19th, 2021 7:22 am

    The ROM image is available for those who’ve purchased the ROM-inator II, but it’s not a disk image – it’s a replacement system ROM with an integrated bootable ROM disk. I don’t think you could use it with Mac software emulators, or would want to. If you’re looking for a “reference” system disk, Macintosh Garden has a lot of great stuff.

  120. Tom - April 19th, 2021 10:00 am

    Thanks Steve. I understand, it’s a ROM image, not a disk image. I just mean it would be useful to be able to use it with an emulator when creating disk images for my SE/30, not to try to use the ROM image as a disk image. I have purchased the ROMinator II – two of them, in fact. So how would I go about getting the ROM image?

  121. Steve - April 19th, 2021 10:10 am

    Sure, I will follow up with you directly. If I understand your question correctly, I don’t think this will do what you’re looking for with the software emulator.

  122. J Thompson - June 1st, 2021 1:47 pm

    Any chance this may work on a Macintosh LC?

  123. Steve - June 1st, 2021 4:57 pm

    Nope, sorry. Please see the list of supported computer models in the first paragraph.

  124. Kiyoshi - October 24th, 2021 2:48 pm

    Macintosh IIvi and IIvx supported? Call me crazy.

  125. Dan+Draper - April 4th, 2022 4:42 pm

    Hey Steve! So I just got a DiiMO 50MHz accelerator card for my SE/30… It works great and the DiiMO and ROMinator II play nicely together but I noticed a funny thing that I wondered if anyone else has reported yet. When I boot the Mac with the accelerator installed, the ROMinator’s boot chime is noticeably slowed down. It’s not a big difference and it doesn’t sound distorted but it is affected. I wondered if it has something to do with the computer swapping between the processors right when the ROM plays the chime, but I’m not an expert. It’s not an annoyance and this isn’t a complaint; I thought it was funny and wondered if you were aware. If you’re interested I can send you a video of it. Thanks for making all this awesome stuff! — Dan

  126. LD - June 10th, 2022 3:36 pm

    Hey Steve! I was under the impression I could use this to boot a computer with system issues. I am likely missing something but is there any documentation on how to restore system 7 with the utility programs. Currently, they don’t open and there are no other apple menu options outside of about this mac. Thanks in advance from a green macintosh newbie!

  127. Steve - June 14th, 2022 8:32 pm

    Yes the ROM-inator II’s built-in ROM disk can boot a computer with a hard drive that’s broken, erased, or missing. It contains a minimal version of System 7 plus some utilities that are helpful for hardware troubleshooting. If you want to install System 7 (full version) on a blank hard disk then you don’t need the ROM-inator. Normally you would boot from Apple’s System 7 installer floppy disks, which will walk you through the steps.

  128. Federico Lucifredi - June 17th, 2022 8:13 pm

    I have a situation with TWO se/30 boards that boot ok with 8MB and display s horizontal bar pattern and fail to boot with larger amounts.

    The same happens with the original ROM and with the Rominator — what am I doing wrong?

  129. Steve - June 18th, 2022 7:21 am

    If you’re seeing strange symptoms even with the original ROM, then it sounds like an SE/30 hardware problem unrelated to the ROM-inator. Check out

  130. andy diller - September 17th, 2022 4:41 pm

    Just a note: Rominator 2 in my MacSE/30 works fine with the Diimo 50mhz accellerator card.

  131. Sean Redmond - October 3rd, 2022 10:46 am

    I have a new IIfx.
    I stuck in 64 MBs of RAM assembled by the 68kmla user hyperneogeo.
    I stuck in a Mega and the Mac-ROM-inator II booted up nicely.
    I stuck in a SCSI2SD v6 with a 32GB SD card partitioned into 8 volumes (all but 1 are 1.99GBs or smaller).
    I installed System 6.0.8 from installers on the SD card and I could boot from the System 6 volume.
    I installed System 7.1.2 from installers on the SD card and I was not let boot from the System 7 volume.
    Since then I can not boot at all from the SCSI2SD card.
    I keep getting the same error message, “This startup disk will not work on this Macintosh model (and so on)”.
    I have tried SystemPicker to no avail. I ran Norton Utilities 2.0, also to no avail. The application with the ambulance-icon (the name escapes me now) was used to check the volumes. All OK.

    I would be happy to hear if any ideas come to mind.

  132. Steve - October 6th, 2022 9:57 pm

    Hi Sean, you can boot from the ROM-inator’s built-in ROM disk, and use the included utility software to reformat your SCSI drive if necessary. It sounds like you may have the wrong System version for your Mac, or some other problem with the System install in the SCSI drive.

  133. Sean Redmond - October 6th, 2022 10:05 pm

    Hi Steve,

    This is what I shall have to do. I suspect that some of metadata in one of the initial partitions has had false data written to it, probably after I installed System 7.1.2. When I copy across the system folder from the Mega-ROM and boot from that, I get the same message.

    Thanks for the reply,

  134. Steve Hammond - June 18th, 2023 5:48 pm

    Hi Steve,

    Do you know if it has ever been tested on a Color Classic, assuming someone solder a slot for the ROM? There’s an available position on the board that looks like a ROM slot that was never used.

  135. Steve - June 19th, 2023 7:11 am

    The ROM-inator II base ROM is a modified Macintosh IIsi ROM, and as far as I know it won’t work in a Color Classic. Same for the IIvi and IIvx, which also have a physically-compatible ROM SIMM slot but are not binary compatible.

  136. Barry - September 28th, 2023 6:33 pm


    The new Rominator works to boot my se-30, but will not find my SCSI hard drive. SCSI prob sees something on the bus at ID0 but says no usable drive found. I know your HD SC Setup 7.3.5 is patched for non apple drives, so any clues would be great. The chain is terminated properly so no issue there it appears. Thanks for any help.

  137. Steve - September 28th, 2023 7:34 pm

    Unfortunately I’m not able to offer help for SCSI drive failures. You may have a SCSI chain problem or if it’s an old drive it might simply be dead. For this type of issue I’d recommend joining or the Vintage Apple Macintosh Enthusiasts group on Facebook. /r/vintagecomputing on Reddit is another good resource.

  138. JB - December 1st, 2023 1:12 am

    Hi, question regarding supported hardware. Not so familar with the models.

    I would like to insert this solution for a mac se. It has a 20 megabyte hd inside but it is just called mac se. Does this work? Thx

  139. Steve - December 1st, 2023 8:19 am

    Compatibility: The ROM SIMM and pre-programmed ROM contents are compatible with the Macintosh SE/30, IIx, IIcx, IIci, IIfx, and IIsi. Note the Macintosh SE differs from the SE/30 internally, and is not compatible with the ROM-inator II.

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