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According to ADC documentation:

You can access Open Firmware this by holding down Command-Option-O-F at boot time.

However, in reality this does not work on current hardware. Does anybody know if there is a way (through trigger-keys, etc.) to get to an EFI console on contemporary-architecture (i.e., Intel) Macs?

EDIT: I am attempting to set up (and document) various Kernel Debug environments.

In experimenting with the boot-loading mechanisms of OS X, I have come to the following conclusion:

  • There are at least 3 different architectures:

    1. Open Firmware (PowerPC hardware)

    2. EFI, in which rEFIt works properly

    3. a transitional(?) EFI [32bit?] which is used on early Intel machines, where rEFIt does not work

I had posted this question after encountering this 3rd case, which seems to occur on Core Duo (not Core 2 Duo!) machines: the result being that, once rEFIt is installed, the rEFIt menu DOES correctly get displayed at boot time, however is unusable because it receives no keyboard or mouse input (no USB drivers loaded?) and ultimately always ends up booting into the highest numbered boot partition.

Therefore, in scouring ADC documents and looking for a means to drop into a firmware/EFI console at boot-time, I came across the (somewhat outdated) statement from ADC [see above] and thought that it might be useful to ask on SO if anyone knew of an alternative.

Cajunluke
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kent
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  • Perhaps you should explain why this is programming related. Else I suspect it'll be closed as "Belongs on serverfault"... – dmckee --- ex-moderator kitten Apr 22 '09 at 14:25
  • hmm... so kernel programming is no longer programming related? this ADC quote comes from here: http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming |K – kent Apr 22 '09 at 15:20
  • Kernel programming is a good SO topic. But when you don't say as much people might miss your intent. A quick edit really would help here. Cheers. – dmckee --- ex-moderator kitten Apr 22 '09 at 15:52
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    Unfortunately asking for key codes is not quite kernel programming. – lothar Apr 22 '09 at 22:39
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    and because I am new here means that you all have the right to bash on me for asking a question? not so cool. – kent Apr 23 '09 at 08:46
  • It's still not closed, so don't feel bashed. People here are just picky about what's programming related. ;-) – lothar Apr 23 '09 at 15:38
  • Is it worth sending an email to the author of rEFIt to see if he's come across your Core Duo issue in his testing? He may be able to shed some light? There are some troubleshooting items which he lists on his site related to keyboard problems, but I think they're unrelated to your issue. – binarybob Apr 24 '09 at 08:39

4 Answers4

7

Only Macs with PowerPC architecture have Open Firmware. The newer Intel based macs have EFI. As these firmwares are completely different their functionality is not equal.

AFAIK EFI does not have the corresponding feature of Open Firmware Access.

lothar
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7

The following quote comes from MacForensics.pdf

Apple does not offer any direct tools for accessing EFI. There is no key sequence available to enter EFI upon boot. There are, however, utilities available to access this. One such tool, rEFIt, is available on Sourceforge.net. The link at the time of this writing is http://refit.sourceforge.net/

Cajunluke
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kent
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    the www.macosxforensics.com site is very interesting in terms of tools and techniques used by law enforcement on suspect macintosh computers... – kent Apr 24 '09 at 11:56
5

As has already been pointed out, Intel Macs have EFI. However, booting from a CD with rEFIT installed (download the "6.5M ISO disk image", burn to disk using Disk Utility, then reboot holding down the 'C' key), you can select an option to Start EFI shell (its the leftmost icon on the bottom row on my Mac) which may be what you want?

binarybob
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2

There is Refit (http://refit.sourceforge.net/) that is a "boot menu and maintenance toolkit", but I'm not sure if it covers the same functionality as the Open Firmware console.

pgb
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