mac pro 3,1 efi modification ?

Hellow !
i have a question, i try to make it short and simple...

do you think it's possible to modify portion of the efi to allow a mac pro (pre-trashcan of course ) to initialize a non flashed "pc" graphic card, with only legacy rom or with hybrid legacy/uefi rom, for having the bootscreen ?

i have no idea about that... maybe something is doable since mac are able to switch in "pc bios" mode.

thanks

yes it's entirely possible to do this. if you wanted help flashing a graphics card, i could help with that. if you want a simple solution, i would explore hackintosh threads.

my favorite forum is tonymacx86.com

i have a fully functioning hackintosh built inside a powermac g5 case, it thinks it is an iMac, and it's running a gtx760 4gb and i have a full boot screen with the help of the clover boot loader.

Hi

but this is not exactly my question, i know this is entierly possible with hackintosh (i do hackintosh for several years now)
but my question is, is it possible to modify a real mac pro efi to make it able to natively initialize any pc graphic card (with legacy or hybrid legacy/uefi rom)
so, this way, you don't need to flash graphic card anymore.

otherwise, yes, if you can help me for flashing a gtx780 it's really welcome

thank you

Perhaps I was unclear. You can use hackintosh tools on a genuine Mac.

In this instance, install clover or other bootloader and configure it for your gfx card

oh yes, i already try that. i tried with chameleon and clover.
but with chameleon, osx boot end in KP (with absolutely no options and config file at all)
and with clover, i don't understand how to make it boot in legacy mode on a real mac.

you cannot use chameleon on genuine mac, it must be clover or the like.

have you got clover configurator?

Edit:

You will not boot genuine mac in legacy mode for this. You will not edit the EFI for this. The bootloader (clover in your example) will simply substitute information passed from the EFI to the OS and vice versa.

With clover configurator it's very easy to inject nvdia settings for your card and it will work automatically, just as it does with your hackintosh. Furthermore you can then disable the clover boot menu and you won't even know it's there.

i think chameleon should work too, i could started a good old iatkos 10.6.3 distro dvd on my mac pro. and with a non flashed pc graphic card (a gtx 650)
i didn't try to install it, but i will test this to see what happen after install.

clover could work in native mode, but, you can only get the clover menu with a non flashed graphic card. and... only if the rom have uefi support in it.
once you passed clover, screen turn black again until osx has loaded. (i tried this with a R9 270x with hybrid uefi/legacy rom and a GTX 650 with legacy rom)

So with clover, are you forcing nvidia and adding ID for both cards? You will disable clover boot menu.

Are you using clover configurator utility?

You should install new gfx adapter, then when OS is loaded, adjust your config.plist for new graphics card.

It may take some trial and error to get it right, but consult hackintosh guides for settings. Those nvidia cards should work OOB for the OS like you mentioned, but it takes some tweaking and whatnot to get the progress bar screen to show.

Adjust your confit.plist and reboot, if you don't see the progress bar, make new adjustments and try again.

What if any bootargs are you adding with clover?

I would not attempt this with hybrid scheme, it should be entirely possible (and easier?) with UEFI boot.

so, if i understand well...
you say it's possible to initialize a legacy pc graphic card rom, through clover in native efi mode to have bootscreen ? but from my experience with a gtx 650, clover menu don't show up at all on this card. he only show up with my r9 270x.
i didn't try to play with arguments or tweak for gfx.

i'm gonna try, but it's hard when clover won't show up
i'm nearly sure he can't show up on a mac with a pc graphic card wich didn't have uefi rom portion.

but to be clear, yes, all if this card i speak here (gtx 650/780, r9 270x) can work oob with osx (10.8.3+ for all this one) without any tweaks.
my problem is not to get them working under osx, it's only to have access at the bootscreen and boot menu. all of this, without flashing.

Yes. That is correct.

Clover configurator (if you're not familiar) is an app launched from within OS X. While you may not have access to the boot screen, you can use the configurator to quickly and easily mount your EFI partition and edit your working config.plist.

There is an entire pref pane for gfx settings.

Once the OS has loaded, make our changes in the configurator and save the plist and reboot.

You do not have to manually add bootargs from the boot screen.

ok, i'll try to see that (i don't use clover configurator, i go directly with plist edit pro, an old way, but i'm fine with )
and if i have good results, i'll tell you.

thanks again

Manually editing the plist is good to know how to do. I used to do that as such, but got tired of reading lists of options and arguments to try.

Much better to tick a box (-:

Good luck