These are replacement ROM chips for the Macintosh 128K, 512K, 512Ke or Plus computers. They are sold as a set of 2, the "HI" chip and the "LO" chip. They are burned onto brand new 27C512 EPROMs.

Please choose the correct version from the list for your Mac. For the Mac Plus there 3 versions; 1, 2 , or 3. Unless otherwise specified I will ship version 3 for the Mac Plus orders.

The Mac 512Ke ROM is the same as the Mac Plus ROM. You can also use this ROM in 512K machine and it essentially turns it into a 512Ke. The only difference would be whether you have an 800k floppy drive - but either should work. So, if you have an actual Mac 512Ke machine, order the Mac Plus ROM. If you have a Mac 512K computer, you may order either the 512K ROM or the Mac Plus ROM - it's up to you if you want to keep it more original, or add the ability for the 800k floppy drive.

Please contact me if you have any questions.