[coreboot] coreboot port for macbook2,1

Vladimir 'φ-coder/phcoder' Serbinenko phcoder at gmail.com
Mon Feb 3 21:58:56 CET 2014

On 03.02.2014 21:43, Mono wrote:
> Hallo Vladimir, Peter and Stefan
> thank you for your emails! You already helped me alot. I don't expect to successfully close this project in a fast run and I'm willing to learn a number of tools.
> At the moment I am still collecting hardware informations about this computer.

> I dissembled it completely and documented the chip names of what I thought might be of interest.

> Please see http://macbook.donderklumpen.de/coreboot/ for what I got.

That is good example of relevant info collection.

> My biggest concern is with the EC.

> It is a Renesas H8S/2116V. I read about this chip that it makes coreboot impossible on other machines,

> but I do not know whether this issue is machine specific, or if the chip definitely makes coreboot impossible for this macbook too.

> Could you comment on this?

Type of EC doesn't matter. What matters is how it is connected. It may
really get in the way or have almost no impact. My guess would be that
on your system its influence is minor.
X60 has H8 as well but with very different firmware which makes it a
completely different chip from coreboot perspective.
> Also I do not know yet how I could verify whether the EC shares memory with the main system.
That flashrom didn't create any ill effects when reading is an
indication of separate flash. If you can flash externally you can leave
the issue of internal flash for later and if you don't, don't flash.
> As for the ability of flashing the EPROM chip, I plan to test it in the near future

> (at first with an empty brand new chip, then with the soldered one). The EPROM is supported by flashrom

> and I plan to use a Beaglebone Black to be the programmer. (this page shows Beaglebone Black can

> flash a chip via SPI also flashrom is not used here: http://www.linux.com/learn/tutorials/746860-how-to-access-chips-over-the-spi-on-beaglebone-black )

> I already learned how to use the Beaglebone Black to debug what coreboot outputs to the USB port on a Thinkpad X60.

> I assume this should work the same for the macbook (the debug port at the macbook seems to exist, but the factory BIOS does not write anything to it). 
> One more question: The macbook atm uses a 32bit EFI which when it was purchased booted a 32bit kernel,

> and today boots a 64bit linux-libre kernel. Would I need to expect any additional problems from the fact that

> it is not a traditional BIOS, but some EFI which is to be replaced? My optimistic wish is to replace that

> EFI with coreboot plus a 64bit GRUB2 payload (same as done on my Thinkpad X60). Or would the payload need to be kept at 32bit?
What Apple ships as firmware is irrelevant.
However, decision to omit BIOS comes from higher-level decision of
omiting compatibility with 95-era systems. So it's possible you won't be
able to boot old OS even with coreboot due to lack of compatibility
devices. I'd say it's a minor problem (95-era OS wouldn't work reliably
on modern system anyway)
> thanks again and
> with best regards
> Mono
> On Wed, Jan 29, 2014 at 10:24:58PM +0100, Stefan Reinauer wrote:
>> * Mono <mono at posteo.de> [140124 23:20]:
>>> Hallo,
>>> Would you help me on a coreboot port? I just installed coreboot on a Thinkpad X60 following the wiki. Now I want it on this mid-2007 macbook2,1 too.
>>> I read some pages in the wiki and started to collect information about the macbook. it seems it has no superIO chip and I dont know what to think of the ectool output. As I understood by now, not knowing how the ec might interfere with the bios or coreboot is one of the big obstacles, no? I hope that once I would try a coreboot flash, recovery might be possible by an external programmer (which I do not have, yet). the flash chip is the same as on the X60 (I've read the factory bios already) as is the northbridge and southbridge. an usb debug port seems available.
>>> I've put the log files here: http://macbook.donderklumpen.de/coreboot/
>>> Any comment about what you think about this and how I should proceed is very much welcome!
>> - Make sure you have the external tools in place to recover from a bad
>>   flash. You will notg boot successfully on the first attempt.
>> - Keep a copy of the original firmware around
>> - Try to make sure that your USB debug gadget is working before starting
>> - Start with one of the existing i945 based notebooks
>> - find out what EC is used, and if it shares flash with the main system
>> - try to get hold of schematics
>> Regards,
>> Stefan
>> -- 
>> coreboot mailing list: coreboot at coreboot.org
>> http://www.coreboot.org/mailman/listinfo/coreboot

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