I have noticed that witth Mac OS 7.5.5 or 7.6.1 it seems to remember the settings and apply them during startup even if the battery is dead (ie the "Welcome to Mac OS" screen is in black and white, but when it changes to "Starting up..." it is in colour). I'm assuming yours has an older OS (7.0/7.1) on it and so that is why you are getting this issue.

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I have assumed (because PRAM-zapping will reduce a display to B&W) that PRAM then specifies 1-bit, but when the System gets far enough into the startup sequence to read Preferences, colour is restored. I agree that this can often be seen in the Systems/OSs that you mention, having seen much of that kind of behaviour this weekend just past (in our part of the world) in a Q950.

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