Macintosh ROM Secrets

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Original document is located at https://cdn.preterhuman.net/texts/computing/macintosh/ROM_Easter_Eggs.txt

Subj: clearing things up...                                            (50/50)
From: The Cloud #8 Last on: 11/23/90
Date: Fri, Nov 23, 1990 2:36:06 AM

Macintosh ROM Secrets
---------------------
 
1) THE SE ROM SLIDESHOW
 
  In the ROM of the original Macintosh SE (*not* the SE/30!) is a four-frame
  slideshow composed of digitized b&w images of the development team.
 
  To view the slideshow, hit the interrupt switch to enter the debugger,
  and type the following:  G 41D89A <return>.
 
  Alternatively, you can write a program which calls this procedure:
 
  PROCEDURE DoIt;
  Inline $4EF9, $0041, $D89A;  { jmp $41D89A }
 
  The slideshow is an endless loop; once started, the only way to quit
  is by rebooting (or turning the power off).
 
 
--
2) THE "STOLEN FROM APPLE COMPUTER" ICON
 
  This icon lurks in the ROM of *every* Macintosh produced.  Rumor has it
  that code to display this icon also exists in ROM, so that an Apple
  employee/wizard could walk up to a potential Macintosh clone, type a few
  commands, and verify that the machine's ROM was in fact "stolen".
 
  This icon exists at different locations in different versions of ROM;
  currently, yours truly has only been able to verify its existence in
  two of those versions:
 
  ROM Version 117, rev.1-3 (Macintosh Plus):              $0040E132
  ROM Version 120, rev. 3  (Macintosh IIx, IIcx, SE/30):  $408A065A
 
  If you have access to other machines, you can use the Graphic memory display
  feature of SUM II Tools 2.0 to locate the icon. (Be sure to set the memory
  base to $40800000, the starting address of ROM on the Mac II series, or
  $00400000 on a Mac Plus or earlier machine.)
 
  It's reasonable simple to write a program that displays the "stolen icon".
  Here's a THINK C function that does the job:
 
  PlotStolenIcon(inRect)
  Rect *inRect;
  {    
    asm {
      BRA.S     @2
@1    DC.L      0x40E132       ;address of icon (Mac Plus ROM only!)
@2    MOVE.L    inRect,-(SP)   ;push rect argument
      PEA       @1             ;push "handle" to icon
      DC.W      0xA94B         ;_PlotIcon
    }
  }
 
--
3) HIDDEN COLOR PICTURES IN THE IIci AND IIfx
 
  The 512K ROM (also known as the first "32-Bit Clean" ROM) introduced with
  the Macintosh IIci evidently had some extra room for fun.
 
  On the IIci, do the following:
    A) Go into the Control Panel and set the date to Sept. 20, 1989
       (9/20/89 -- this just happens to be the machine's release date.)
    B) Reboot and hold down cmd-option-c-i (yes, all 4 keys simultaneously.)
    C) Surprise! Up pops a color picture of some Apple employees!
 
  On the IIfx, the procedure is similar:
    A) Set the date to March 19, 1990  (3/19/90 -- the release date.)
    B) Reboot while holding down cmd-option-f-x.
    C) Yes, it's another color picture!
 
 
--
4) HIDDEN STARTUP DISK IN CLASSIC ROM
 
  The Macintosh Classic has an "undocumented feature":  a complete, bootable
  system "disk" in ROM.  This was an experiment in creating a "diskless
  workstation" machine that apparently wasn't considered important enough
  to mention as a feature.  Rumor has it that the Macintosh LC and IIsi also
  contain a hidden ROM disk, but this has not yet been verified.
 
  To access the hidden disk, reboot the Macintosh Classic while holding
  down cmd-option-x-o.  When the Finder comes up, the ROM disk should appear
  on the desktop.  Note that you can use the Startup Device cdev to specify
  this disk as the startup device;  subsequently, the machine will boot from
  ROM without the need for a "real" startup disk (handy, if you've only got
  one floppy disk drive.)
 
 
--
5) ???


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