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Author Topic: GTX 770 Mac  (Read 71390 times)
Fl0r!an
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« Reply #30 on: August 17, 2015, 09:23:20 PM »

Inserting
Code:
f.read(1024)
after line 103 of fixrom.py will make it skip the 1024 byte section at the beginning. Results look plausible to me.

EDIT: Whoops, I was looking just for the checksum but didn't realize that this will leave out this 1024 byte section in the resulting file. I'll fix it later.
« Last Edit: August 18, 2015, 07:29:07 AM by Fl0r!an » Logged
rankel
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« Reply #31 on: August 20, 2015, 04:40:12 AM »

Something I am doing is structurally wrong. I am attempting a very simple and cosmetic change in the 680 rom, for use with a 680 card. Simply changing the rom revision string, running the headless rom through fixrom, making the changes made by the script in the full rom (with the first 1024 bytes intact) manually, and flashing that rom to the card bricks the card.
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Fl0r!an
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« Reply #32 on: August 20, 2015, 08:03:52 AM »

I guess that's what Rominator meant with "sections are interlinked". I'd search for the checksum  (or something similar) in the other sections, maybe by comparing K5000 vs. GTX680.
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rankel
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« Reply #33 on: August 20, 2015, 07:16:28 PM »

Yes, I suppose I should look for each checksum manually. Now I am a bit confused about what needs to be done with the checksum. Is it changed by modifying the rom, and needs to be changed back to its original value by changing the 00 or ff bytes at the end of a section, or does it need to be recalculated and changed to its actual value?

There seems to be quite a lot of conflicting information out there, perhaps because checksums are calculated and used in different way for different applications.
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Fl0r!an
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« Reply #34 on: August 25, 2015, 05:08:30 PM »

Just dug a little through the Q4000 Fermi EFI. Quite funny that it contains a reasonably long list of Nvidia device IDs, from GTX 480 (which never existed as Mac card if I remember correctly?!) over GTX 280 to legacy 9xxx and 8xxx cards. Seems to have a rather ancient code base  Grin



Same story for GTX 680 EFI, contains some other Kepler cards and GTX 4xx/5xx Fermis.
Obviously no 770 as this wasn't released back then...
« Last Edit: August 25, 2015, 05:10:31 PM by Fl0r!an » Logged
Rominator
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« Reply #35 on: August 25, 2015, 08:59:44 PM »

Yes. I was pretty sure that a 480 was tested but never happened for some reason, possibly power issue.

The NVIDIA EFI got added to over the years, not rewritten.

It has issues with some cards., some output combos and requires extensive work for newer cards. Was pretty amazing and fun figuring it out.
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Fl0r!an
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« Reply #36 on: August 25, 2015, 10:59:40 PM »

Did you ever try using the Kepler EFI with a 5xx card? I saw you're selling yours with just 2 functional ports, maybe this would work better since GTX 680 has 4?
Obviously you didn't have a Kepler EFI available when you worked on 5xx, but it would be still very interesting...
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Rominator
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« Reply #37 on: August 25, 2015, 11:38:26 PM »

That is limit of the card itself

Even in Windows it only creates 2 desktop images.

I could probably go back and write better roms that allowed some dynamic switching but there is little point now.
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Sebinouse
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« Reply #38 on: August 26, 2015, 05:46:43 PM »

Noob question here : how do you manage to get IDA Pro to open your ROMs ?

Mine (Mac 6.2) keeps crashing, I also tried Hopper which cannot open the .rom files ...

Is there any other solution to disassemble .rom files ?
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Fl0r!an
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« Reply #39 on: August 26, 2015, 05:48:40 PM »

You have to extract and efi-decompress the EFI part of the rom.
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Sebinouse
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« Reply #40 on: August 26, 2015, 06:10:41 PM »

OK and how can I do that ?  Huh

I used to play with .fd and .efi ... but with hexfiend (simple hex editor) ... but this time it is not that simple ...
« Last Edit: August 26, 2015, 06:18:43 PM by Sebinouse » Logged
Fl0r!an
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« Reply #41 on: August 26, 2015, 06:38:07 PM »

The command line tool 'UEFIRomExtract' can do this automatically (at least I think so, I'm not 100% sure it understands Kepler ROMs).
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Fl0r!an
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« Reply #42 on: August 28, 2015, 08:51:28 PM »

Okay Nvidia, here I come...  Cheesy




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Fl0r!an
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« Reply #43 on: August 29, 2015, 06:32:49 PM »

I guess MVC has seen this picture quite often?  Cheesy


And you know this stuff by heart by now? ftp://download.nvidia.com/open-gpu-doc/DCB/1/DCB-4.0-Specification.html  Smiley
Oh and I'm sure that's no news to you, but that 'NvidiaInfo' app from InsanelyMac is extremely useful. Shocked
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Rominator
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« Reply #44 on: September 01, 2015, 05:17:35 AM »

link not working for me
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