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Determining the version of Open Firmware on your Mac

Q: How do I tell which version of Open Firmware is on my Mac? I understand that version 3 came out with the iMac. What about Macintoshes after the iMac?

A: You can tell the Open Firmware version by the header message that is presented to the Open Firmware user interface.

Start your Macintosh holding down the Command-Option-O-F keys and wait until the Open Firmware message is displayed. Here is the header for a 1999 Power Macintosh G3 Macintosh (a.k.a., the blue & white or 1999 Power Mac G3):

Apple PowerMac1,1 1.0f3 BootROM built on 12/08/98 at 17:37:02
Copyright 1994-1998 Apple Computer, Inc.
All Rights Reserved.
OpenFirmware 3.1.0

[Mar 29 1999]

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