iM 4,1-14,4 2011 iMac Graphics Card Upgrade

[biohead]

I’m not entirely clear what the purpose of the vbios files are for (obviously for the graphics card, but why?).

I’m looking at dropping a K610M in (readily available to me) as I just want a way to run Mojave and don’t need any gfx horsepower.

As the K610 isn’t available in any other Mac, would this be a much more substantial vbios mod? Happy to give it a go myself in terms bios, I just want to understand the theory a bit more. No issues with the bootrom and why that’s needed.

 

[Mr-Mur]

About bootrom mod..
Nick [D]vB, can you post a detailed manual from A to Z of making this correctly?

I'll try to make this procedute completely.

 

[jmilan0302]

I’m not entirely clear what the purpose of the vbios files are for (obviously for the graphics card, but why?).

I’m looking at dropping a K610M in (readily available to me) as I just want a way to run Mojave and don’t need any gfx horsepower.

As the K610 isn’t available in any other Mac, would this be a much more substantial vbios mod? Happy to give it a go myself in terms bios, I just want to understand the theory a bit more. No issues with the bootrom and why that’s needed.

The vbios and bootrom mods are to get EFI boot menu and bootscreen. I doubt the K610M will work but you could always just try. The 765M and K2000M were never available in a Mac either.

 

[FlorisVN]

About bootrom mod..
Nick [D]vB, can you post a detailed manual from A to Z of making this correctly?

I'll try to make this procedute completely.

I would love to help on that, currently at the last stage here, about trying to flash the bootrom.
already done the vbios mod on my GTX765m.

 

[Mr-Mur]

I would love to help on that, currently at the last stage here, about trying to flash the bootrom.
already done the vbios mod on my GTX765m.

If bootrom mod can help solving bootscreen issue, I am ready to disassembly my iMac and make detailed report of this, this pictures etc

 

[FlorisVN]

If bootrom mod can help solving bootscreen issue, I am ready to disassembly my iMac and make detailed report of this, this pictures etc

yes, bootrom combined with vbios will give bootscreen.
like @Nick [D]vB posted !

For amd cards RX580/560 he also posted vbios and bootrom patch.
but keep in mind these amd cards also need a backlight mod, which the nvidia ones wont need.

If you can help with a detailed guide, that would be great !
i'm currently in the last stage of trying to mod the iMac's bootrom.

 

[Mr-Mur]

I found Eeeprom chip model (at least, for my 27'' 2011): MX25L6406EM2I-12G
It is 64Mb chip, I am planning to buy 2 of them

 

[Nick [D]vB]

No need to replace the chip, unless something goes badly wrong!

You do not need to solder anything or even remove the logic board,

just program the existing chip using a programmer + test clip.

 

[Mr-Mur]

No need to replace the chip, unless something goes badly wrong!

You do not need to solder anything or even remove the logic board,

just program the existing chip using a programmer + test clip.

Just in case, let them be

 

[Nick [D]vB]

ok then! xD

 

[Zulus555]

Updating ONLY vbios did not give a boot screen ...

 

[Nick [D]vB]

Yes that is correct, no Apple bootscreen without the bootrom mod,

but you should have a Windows boot-screen now after the vBIOS flash,

I think you said that Windows is the only OS you have installed?

 

[Zulus555]

Yes that is correct, no Apple bootscreen without the bootrom mod,

but you should have a Windows boot-screen now after the vBIOS flash,

I think you said that Windows is the only OS you have installed?

Yes, I only have the Windows system installed. After updating vbios, nothing has changed. I do not see the screen as in the picture.

Screenshots before and after the update.

 

[FlorisVN]

Yes, I only have the Windows system installed. After updating vbios, nothing has changed. I do not see the screen as in the picture.

strange, I did get an windows bootscreen.
but I do want to note, Im running Windows 7 Ultimate 64 Bit here, and it does not run in UEFI mode, but legacy bios mode..

also running a GTX765M here, what are you using.. ?

 

[Zulus555]

I use Windows 10 64bit. Video card 770m, screenshots of its firmware post above. Thank you for attention.

 

[Nick [D]vB]

Boot screens only work in legacy Windows mode, run msinfo32 to check your BIOS boot mode.

If you install in UEFI mode you will have many problems on these iMacs, iGPU BSOD crashes etc

Do your iMac speakers work? I had to make a special patch to fix the HD audio driver in UEFI mode.

If you want to install in legacy mode you must use a DVD not USB stick, or modify the installer config.

 

[Roman78]

But it is higher clocked.

 

[Nick [D]vB]

Yes, it would be interesting if you can post Valley / 3Dmark benchmarks before and after the vbios flash.

You can also overclock in Windows, I got one card to 1GHz with extra cooling, but it was not very stable.

 

[FlorisVN]

got a bootscreen now with GTX765m, special thx to @Nick [D]vB and others who helped with these bootrom/vbios mods !!!!

The whole procedure was easier than I thought initially.
Now I only have to learn how to mod the bootrom code, Nick was so kind to mod one for me.
But Shouldn't be so hard I guess, and he also made a nice tot. video about it !!

Special thx again @Nick [D]vB !

Target disk mode now btw also works

I'm planning on making a small demo video soon, just a small demonstration video..
Currently my only issue is, that you turn it on it gives a black screen for a while, like before without the bootrom mod.
and suddenly gives the usual macOS white screen and loading bar.
I was used to see a white screen immediately when you turn on the iMac, with the original AMD card.

But Nick says he does not have this problem, so we will have to look into this..

Having a bootscreen now, saves lots of hassle for us wanting to install a patched Mojave or Catalina..
I never thought I would see a bootscreen again, with my upgraded card..

Thx again for this great work, and sharing !!

 

[iGermannn]

Nick [D]vB If it was possible to create vBios & Bootrom mod for K2000M it would be great, I think many people have this GPU installed in iMacs . Thanks for your fantastic work.​

 

[biohead]

Nick [D]vB If it was possible to create vBios & Bootrom mod for K2000M it would be great, I think many people have this GPU installed in iMacs . Thanks for your fantastic work.​

I'd be interested to know HOW you do this - as I'd like to attempt the same for the K610M.

 

[Mr-Mur]

First steps: I dumped my ROM (iMac12,2, BootROM 87.0.0.0.0, SMC 1.72f1)

Note: when dumping with a ROMTool, I checked MX25L6406E option (second)
[doublepost=1567786574][/doublepost]

got a bootscreen now with GTX765m, special thx to @Nick [D]vB and others who helped with these bootrom/vbios mods !!!!

Congratulations! Please, make a video of starting up your iMac, showing bootscreen? (Also, boot menu with Option key pressed at startup)

Thank you!

 

[Nick [D]vB]

It is best not to post Bootrom dumps publically! They contain personal information, serial numbers etc!

People really should dump & mod their own Bootrom, not use ones from other iMacs! It is very easy to do.

 

[FlorisVN]

First steps: I dumped my ROM (iMac12,2, BootROM 87.0.0.0.0, SMC 1.72f1)

Note: when dumping with a ROMTool, I checked MX25L6406E option (second)
[doublepost=1567786574][/doublepost]

Congratulations! Please, make a video of starting up your iMac, showing bootscreen? (Also, boot menu with Option key pressed at startup)

Thank you!

Yes was also planning on doing that kind of video !
[doublepost=1567789921][/doublepost]

Yes, I only have the Windows system installed. After updating vbios, nothing has changed. I do not see the screen as in the picture.

Screenshots before and after the update.

looks way beter if you ask me already, after the vbios mod.
high core clocks, higher memory clocks etc.

You card should perform beter now I would say !
Only a bootrom patch now, and you can also have you bootscreen back if you want..

 

[Roman78]

I just flashed my GTX 765M but stil have no Boot screen on W10. But that could be because of the EFI. But i benchmarked. And i noticed a lot higher Temperature while benchmarking.

Now first step done, now have to order the order some parts.