Editing Macintosh II (section)

=== Expansion ===
Six [[NuBus]] slots were available for expansion (at least one of which had to be used for a [[graphics card]], as the Mac II had no onboard graphics [[chipset]] and the OS didn't support [[Headless computer|headless]] booting). It is possible to connect as many as six displays to a Macintosh II by filling all of the NuBus slots with graphics cards.  Another option for expansion included the [[Mac286]], which included an [[Intel 80286]] chip and could be used for [[MS-DOS]] compatibility.<ref name=":1" />

The original ROMs in the Macintosh II contained a bug that prevented the system from recognizing more than one megabyte of memory address space on a Nubus card. Every Macintosh II manufactured until approximately November 1987 had this defect. This happened because Slot Manager was not 32-bit clean.<ref name=":2">{{cite magazine |magazine=[[InfoWorld]] |date=26 October 1987 |page=47 |volume = 9 |issue = 43 |title= ROM Upgrade to fix bug in Mac II Bus | first = Laurie | last = Flynn | url=https://books.google.com/books?id=_z4EAAAAMBAJ&pg=PA47}}</ref> Apple offered a well-publicized recall of the faulty ROMs and released a program to test whether a particular Macintosh II had the defect.<ref name=":2" />