The new Universal 8MB ROM SIMM is the largest ROM you can buy. It is pre-flashed with the Big Mess o' Wires (BMOW) modified IIsi base ROM and a bootable disk image with System 7.1 Update 3. The BMOW base ROM supports Steve Chamberlin's excellent FC8 compression scheme that allows use of disk images that are up 12MB in size. The Universal ROM SIMM is the ONLY device on the market to work on the normal IIsi base rom machines like other ROMs but will also auto sense to work on Quadra/Performa/LC Machines. See list of machines listed lower. ROM Images will be made available to download from our Github Page as they are released. You will need to use a ROM Simm Programmer and your disk boot image to create your own custom bootable ROM images to work on the Quadra/Performa/LC machines. GitHub download page: github.com/CayMac-Team/UniversalROMImages Be sure to follow this page & Twitter (X) @CayMacVintage for the latest news and releases. You want your Universal ROM SIMM programmed by CayMac Vintage before shipping? Go to the Services section and purchase the ROM Flashing Service for $5.00. ko-fi.com/caymacvintage/commissions#buyShopCommissionModal RECOMMENDED: Make your own bootable disk image filled with your favorite software and flash it to the ROM SIMM yourself using our ROM SIMM Programmer ( ko-fi.com/s/6f9e9644e4 ). The SIMM Programmer app by Downtown Doug Brown ( github.com/dougg3/mac-rom-simm-programmer.software/releases ) makes this process surprisingly easy on a modern Mac or Windows PC. The key advantage of having the Programmer is that you can make different disk images and flash them as often as you like. Mini vMac ( www.gryphel.com/c/minivmac ) is very useful when creating disk images, and Macintosh Garden ( macintoshgarden.org ) has a great software archive. To learn more on the Programmer, watch this great tutorial video made by James Wages at www.youtube.com/watch CayMac Vintage is licensed by BMOW ( www.bigmessowires.com ) to use their base ROM on our ROM SIMMs. Please read the BMOW ROM-inator II page ( www.bigmessowires.com/mac-rom-inator-ii ) for details on features and usage. Macintosh Compatibility (LED will be ON): SE/30, IIx, IIcx, IIsi, IIci, and IIfx. LED will be OFF - may require 64 pin rom simm socket to be installed: Q700/900/950 Q610/650/800 LC475/575/Q605 LC630 & IIvi/IIvx/Pf600 Set Top Television Box 2MB ROM Q840AV NOT SUPPORTED: Q660AV 64 pin SIMM socket can be purchased with your ROM for $5.00 by selecting the purchase option With Socket. WARNING!! Be sure you are comfortable and able to install a socket in your machine. CayMac Vintage is NOT liable and/or responsible for any damage you cause to your board installing the socket. If you are not comfortable doing this, seek service from a person with ability and skill to do it or you can contact CayMac Vintage to make arrangements to send your board in to add the socket. LIMITATION: Booting from ROM only works with BlueSCSI and ZuluSCSI right now. Mechanical hard drives or other SCSI devices have a timing issue with the ROM boot driver causing it to timeout. Hope to have this issue resolved soon, and you would only need to reflash the SIMM with new firmware. IMPORTANT! Some ROM SIMM sockets with plastic tabs may have connectivity issues with non-stock ROM SIMMs. With such sockets, your vintage Mac may not boot, or may intermittently freeze. To eliminate such problems, we provide you with both version of the ROM Clips at no extra cost. Please read this page ( www.printables.com/model/35592-macintosh-se30-rom-clips ) for details about the clip and their usage. ROM Clips are CC BY-SA 4.0 by PotatoFi.