IIGS strange behavior

[retromod-Apple-II-newsgroups; rm -rf ~;@vuse.vanderbilt.edu (Tilghman Lesher)]

I have encountered some EXTREMELY strange behavior while starting up my
Apple IIgs.

When shiftbooting, after the thermometer fills about 15 pixels, a red
X, similar to the X drawn over CDevs at startup when they don't load
properly, is drawn over the "No Inits" message in the middle of the
screen.  Then, most inits, CDevs, and desk accessories load anyway,
INCLUDING those with an auxiliary type of 0x8000 (deactivated).

If I am holding down the Control key at the time, however, the Shift-boot
succeeds, with the only strange behavior being that a green circle is
drawn where the red X otherwise would have been drawn.

I have reformatted the startup drive, replaced ProDOS, GS.OS, and
Start.GS.OS files, and reinstalled all drivers.  I have even restored
the machine/BRAM to defaults.

I cannot explain this behavior in any way.

Possibly, some Tool's BootInit routine may be causing this, as this
is the only thing I can think of that I have not yet eliminated.
However, I don't think many tools have been updated or replaced.

Ideas, anyone?

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