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Mac ROM Secrets, IIci & IIfx color pics Apple employees

7384 Views 2 Replies Latest reply: Nov 10, 2005 11:06 PM by Debberss RSS
Debberss Level 2 Level 2 (245 points)
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Nov 10, 2005 11:06 PM
Thought these were interesting, but I don't have the right models needed to test them. If anyone does, and can try these out and post back on if they work or not.

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:
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).

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:

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
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!


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