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

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The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
Roman78 said:
After i received my programmer i googeld a lot and found the so called CH341A Black Edition Programmer software. It looks like this:

View attachment 862185
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The Chinese, oh, these Chinese ... I finalized the clothespin, the chip was considered. But the picture is different from the picture of Nick ...

Where is SIP cleaned?
 

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Roman78 said:
That is the UEFItool to edit the BootRom. but first you have to download the Bootrom to the computer, and after modifying with the UEFITool you have to upload it again. At least that how i understand and did it. And there for you need the CH341A Program or the one Nick mentioned here: https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-104#post-27680250
Click to expand...


As you can see, I already copied the dump. The question is that it does not look like a dump of respected Nick. The link driver didn’t want to work for me ...
 
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So, yes that is right... now you have to insert the two files. Take a look at this video:


Back to my issue: I just installed Sierra and that worked great. But also on Sierra i don't have a Boot screen. Only on Mojave i have a boot screen. While pressing -ALT- on boot i get screen and can choose the partition an than i have the Boot screen while loading, so the -ALT- triggers the screen. I also noticed on Mojave, and only on Mojave there is a little text before the Apple logo appears. Must be some side effect from the Mojave installer by Dosdude. I think this text also triggers the display to start.
 
FlorisVN said:
i have used flashrom on MacOS, runs great and used it for the bootrom patch here..
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yep done so trough bootcamp using nvidia nvflash,
Click to expand...
very well. Now it remains to wait for the parcel with the video card. But there is generally a detailed instruction on how to flash?
 
Roman78 said:
So, yes that is right... now you have to insert the two files. Take a look at this video:


Back to my issue: I just installed Sierra and that worked great. But also on Sierra i don't have a Boot screen. Only on Mojave i have a boot screen. While pressing -ALT- on boot i get screen and can choose the partition an than i have the Boot screen while loading, so the -ALT- triggers the screen. I also noticed on Mojave, and only on Mojave there is a little text before the Apple logo appears. Must be some side effect from the Mojave installer by Dosdude. I think this text also triggers the display to start.
Click to expand...

iMac 2011 and GTX765m I also see the text in High Sierra before the apple logo appears, but I can't read it because it blinks for a short time. Boot Screen is still missing. I think we mixed up the bootrom, despite the theoretically correct change
 
I've done the GTX765m upgrade on my 21,2 imac and have Mojave running fine. Is the bootrom modification the only thing needed to get the boot screen to work?
 

This post is now out of date, please refer to the first post in this thread for up-to-date info

Underbeat88 said:
very well. Now it remains to wait for the parcel with the video card. But there is generally a detailed instruction on how to flash?
Click to expand...

Complete guide on how to flash your iMac's boot rom and 765m/770m/780m gpu in order to get boot screen and the cards working with both MacOs and Windows:

Please others chime in if I'm incorrect with any of this.

This assumes you either already have Windows installed, or you have the ability to install Windows.
Some of this is how I would go about doing it, as with most things there's other ways and it pretty much comes down to what you're comfortable with.

Edit: updated with correct version of UEFITool



This post is now out of date, please refer to the first post in this thread for up-to-date info
 
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@liquidtwitch If you own a second computer it is much easier. Especially when it runs Windows already, well WinXP or W7. On W10 i was not able to install the CH341A drivers because there were not Digitally signed.

You can also flash the GPU using the CH341A, dont need to install Windows on the iMac. If you allread installed windows using nvflash is easier. And flashing the BootRom is also done in Windows. No need to install Ubuntu.

Underbeat88 said:
this is very good news. I understand the problem with brightness is solved only by installing the pwm module?
Click to expand...

As far as i know, at this moment, yes. I hope there will be a solution for this in near future. Because on Linux (i testet Mint and Ubuntu) the brightness control is working. So it is some how a software issue.
 
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Roman78 said:
You can also flash the GPU using the CH341A, dont need to install Windows on the iMac. If you allread installed windows using nvflash is easier. And flashing the BootRom is also done in Windows. No need to install Ubuntu.
Click to expand...

Ah that's great - I might keep updating my post so people can use it as a central resource.

The reason I opted for ubuntu is because it has out of the box support for the CH341A so I didn't have to use drivers and I could use the flashrom utility.
 
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liquidtwitch said:
Just went to turn my iMac on and it's not POSTing anymore - fans spin up for a second then stops, does this over and over.

I wonder if there's any chance I corrupted the bootrom when I was trying to read it? Otherwise I might need a new board.

Doesn't appear to be any physical damage from where I was trying to clip it:
Click to expand...
Hello! It turned out to launch imac? I have the same symptoms ... The attempt to return the old dump ended in failure - the fans rotate but there is no gong sound.
 
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Roman78 said:
@liquidtwitch If you own a second computer it is much easier. Especially when it runs Windows already, well WinXP or W7. On W10 i was not able to install the CH341A drivers because there were not Digitally signed.

You can also flash the GPU using the CH341A, dont need to install Windows on the iMac. If you allread installed windows using nvflash is easier. And flashing the BootRom is also done in Windows. No need to install Ubuntu.



As far as i know, at this moment, yes. I hope there will be a solution for this in near future. Because on Linux (i testet Mint and Ubuntu) the brightness control is working. So it is some how a software issue.
Click to expand...
Is it possible that the id or serial number of the card does not match what is sewn into the BIOS? Perhaps this is somehow solved by DSDT edits?
 
Zulus555 said:
Hello! It turned out to launch imac? I have the same symptoms ... The attempt to return the old dump ended in failure - the fans rotate but there is no gong sound.
Click to expand...

I had the same problem at one point, but it was because I forgot to reinstall the RAM.

I also found that doing dumps of the boot rom with romtool was a bit unreliable. When the machine didn't freeze, I was able to get two matching dumps of the boot rom, but found that after a reboot, and doing a new dump, something changed. That happened consistently, so I didn't trust the dumps.

Instead of using romtool to do it, I de-soldered the bios chip and dumped it with my old Minipro TL866A EEPROM programmer. I then modified the dump and flashed it back to the same chip. Flashing only takes about a minute with that programmer. I'll note that for anyone else, that my newer TL866II Plus programmer could only copy the EEPROM, but not reliably erase or re-program it (seems to be a software issue).

I ended up doing the same thing with the EEPROM on the graphics card, since I don't have Windows on the Mac - basically just dumped the original rom (just in case) and then flashed Nick's 765M ROM. I did all of the flashing of the EEPROMs while they were desoldered, as the over-current protection on the programmer kept stopping me from doing it in-circuit.

I've now got the Mac working with the GTX 765M installed, but I find that I have to reset the PRAM every time I want to see the thing boot, as otherwise I just get a blank display until MacOS loads. If I reset the PRAM, I can get to the boot menu again.
 
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rmd79 said:
I had the same problem at one point, but it was because I forgot to reinstall the RAM.

I also found that doing dumps of the boot rom with romtool was a bit unreliable. When the machine didn't freeze, I was able to get two matching dumps of the boot rom, but found that after a reboot, and doing a new dump, something changed. That happened consistently, so I didn't trust the dumps.

Instead of using romtool to do it, I de-soldered the bios chip and dumped it with my old Minipro TL866A EEPROM programmer. I then modified the dump and flashed it back to the same chip. Flashing only takes about a minute with that programmer. I'll note that for anyone else, that my newer TL866II Plus programmer could only copy the EEPROM, but not reliably erase or re-program it (seems to be a software issue).

I ended up doing the same thing with the EEPROM on the graphics card, since I don't have Windows on the Mac - basically just dumped the original rom (just in case) and then flashed Nick's 765M ROM. I did all of the flashing of the EEPROMs while they were desoldered, as the over-current protection on the programmer kept stopping me from doing it in-circuit.

I've now got the Mac working with the GTX 765M installed, but I find that I have to reset the PRAM every time I want to see the thing boot, as otherwise I just get a blank display until MacOS loads. If I reset the PRAM, I can get to the boot menu again.
Click to expand...

Black screen delay is normal, this is also what Nick said before, he will try and fix this someday.

There is a dellay when the screen lights up during efi boot.
For example when you press alt (option) key on bootup, it takes about 4-5 seconds when you see the startup selection screen.

There is a delay when you see the bootscreen, especially noticible when you are using ssd.
It boots so fast, that the first few seconds are black due to the delay.

Having different dumps with romtool is normal after restart.
Nick told me this before.

Ive learned that the rom tool is reliable to make dumps, but just set a few minutes between each dump.
Doing multiple fast after eachoter will give you problems.
So take the time when using this tool.

If im correct the amd cards are slightly faster with showing the bootscreen compared to the nvidia kepler cards.

I have not desoldered anything, and the mods are working great here..
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WillD7545 said:
I've done the GTX765m upgrade on my 21,2 imac and have Mojave running fine. Is the bootrom modification the only thing needed to get the boot screen to work?
Click to expand...

Bootscreen patch and new vbios for the gtx765m are needed for a bootscreen.
Use beta2 from Nick !
 
liquidtwitch said:
Please others chime in if I'm incorrect with any of this.

This assumes you either already have Windows installed, or you have the ability to install Windows.
Some of this is how I would go about doing it, as with most things there's other ways and it pretty much comes down to what you're comfortable with.
Click to expand...
liquidtwitch said:
Please others chime in if I'm incorrect with any of this.

This assumes you either already have Windows installed, or you have the ability to install Windows.
Some of this is how I would go about doing it, as with most things there's other ways and it pretty much comes down to what you're comfortable with.
Click to expand...
Thank you for the info. As the package arrives with the video card, I will immediately begin to experiment. I have little experience in arduino firmware, as well as BIOS for desktop PCs. I think that everything will work out)
 
crosyn said:
I can confirm that the Nick's trick works on a 27" late 2009. 👍
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I will give up neither for 2009 nor 2011 I did not succeed despite several attempts. I probably make a mistake when modifying the bootrom, although it is a few clicks like in the movie :(
 
Hey all, I had a long train journey today so had time for some replies, I'm back at home now but I really have to catch-up on some work before I can do any more testing. I will be checking-in here regularly though.

FlorisVN said:
Has somebody here perhaps already made a way possible to disable efi check within MacOS ?

My experience so far you will get efi warnings due too the bootrom patch.
I spoke with nick before in the past, and there should be a way to disable it.


Maybe this link will give us some usefull info about thr efi check deamon..?

pikeralpha.wordpress.com

Apple’s eficheck…

Ok. So you use Clover with an AMI or Phoenix BIOS. Well. In that case you may be interested in this: This is part of routines that wipe data in the generated dump, but why would Apple do this for A…
pikeralpha.wordpress.com pikeralpha.wordpress.com
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Great, currently working on a english version here, and will make a dutch one too..
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I look forward to reading the guides when you have finished them. :)

That EFIcheck is really not a problem, but if it bothers you that link should help us disable it,
the first thing to try is probably just to delete the Launch Daemon:

/System/Library/LaunchDaemons/com.apple.driver.eficheck.plist

If that doesn’t work try deleting the kext (or just remove its execute permissions)

/System/Library/Extensions/eficheck.kext

But if you want to test this remember to disable SIP & make a full MacOS back-up first.

BTW – I was not expecting target display mode to work on the AMD cards, it was not available on iMacs with those GPUs so it is not configured by their EFI, but there is still a small chance it could work on the Kepler cards using the right cables etc.

coolbits said:
Great progress here and many thanks to Nick for vbios and bootrom patches.

I have late 2009 imac with 765m which is now already flashed with Nicks vbios.
Bootrom already patched and just waiting for SOIC8 clip to flash it.

With bootscreen working i will start some more experiments with DSDT tables (im the one who got display brightnes slider to show)
because now i will be able to start without clover efi injections if it blacks out :)
Without bootscreen i had to take out ssd disk and remove DSDT patch with another computer, and that was too much time consuming.
I strongly belive brightness is only software issue on kepler cards.

Has anyone already flashed bootrom to late 2009 imac?
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Good to have you on-board! I did some quick brightness tests a few months back using OpenCore’s ACPI injection, Clover is much more mature so that’s probably a better option, but keep that bootrom back-up handy because I heard it can corrupt the NVRAM volume. I tried naively smooshing together various DSDT / SSDT tables taken from newer iMacs but that mostly resulted in compilation errors and kernel panics - normally related to AGDC. I also got the slider to appear, it just wouldn't do anything. There's something weird going on with multiple “Device LCD” instances, and to be honest I don’t really understand how the graphics EFI injection, DSDT tables, and all the various Kexts interact.

There’s also the problem of the missing “MXM structure” and badly hacked DCB tables which certainly don’t match the original iMac vbios properly. Given all that, the legacy / fall-back solution often used by linux users seems to be the better option; just poking the back-light registers directly using something like setpci, but we’d need to find them first. Chipsec might come in handy here, I was playing with it to fix PCIE bridge config issues (why the new AMD cards need a back-light mod?) but I gave up on that and brightness control months ago - those $2 PWM modules will do the trick. I’ve attached some SSDT files & random links that looked promising, but I’ll freely admit to being out of my depth on this one. Good luck with it! :p;)

liquidtwitch said:
Only got the one romtool backup unfortunately. But I'll try and make a backup of the eeprom once the new clip arrives.

@Nick [D]vB any idea why my rom dump (https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-27783702) looks so different?
Click to expand...
Great write-up, but you have linked the wrong version of UEFI Tool, you must use 0.26. The alpha “NE” versions are read only, still very useful because they display the section & driver names instead of just GUID codes but you can’t edit using it yet. That’s one reason your screen-shot looked different to mine, but most dumps will look a bit different anyway, if UEFI Tool can open the file without a load of error warnings then the dump is probably good. Just insert the driver files before the free space in the first BIOS region, as a rule if you don't see a very long list of DXE drivers you're in the wrong section. I’d question the need to install a Linux virtual machine just to use the CH341A, the drivers are available for almost every OS, but whatever works for you!
liquidtwitch said:
Just went to turn my iMac on and it's not POSTing anymore - fans spin up for a second then stops, does this over and over.

I wonder if there's any chance I corrupted the bootrom when I was trying to read it? Otherwise I might need a new board.

Doesn't appear to be any physical damage from where I was trying to clip it:
Click to expand...
Now I can see the photo you posted properly I’m afraid it looks like you might have damaged the logic-board, there seems to be a SMD resistor missing next to the EEPROM chip, marked R6100 (and possible damage to R6101). I think those are “pull-up” resistors for the EEPROM which is probably why the iMac won’t POST. If you are very lucky you might be able to repair it by bridging the solder pads with graphite from a pencil, you could try and “draw” a few lines to join the dots! It’s an old over-clocking trick but it has been known to work, if not I’m afraid you’ll need to get the soldering iron out, or just get a new board. I can also see the edge of the EEPROM chip package has been ground off by the clip, even the Pomona clip will struggle to hold onto that now, I suggest laying the iMac down on it’s back to give it a fighting chance. The casualties seem to be mounting up fast here, but I guess we can say they died for science, if that’s any consolation… :oops::(

rumian said:
iMac 2011 and GTX765m I also see the text in High Sierra before the apple logo appears, but I can't read it because it blinks for a short time. Boot Screen is still missing. I think we mixed up the bootrom, despite the theoretically correct change
Click to expand...
If you can see that text the mod might actually be working now, do you see the boot-picker by holding Option / ALT after the chime? (you must use an Apple or any wired keyboard) What is shown in About this Mac? Do all 4 debug LEDs on the logic-board light up? If you don’t post any information it will be hard for people to help you...

Zulus555 said:
I have the same symptoms ... The attempt to return the old dump ended in failure - the fans rotate but there is no gong sound.
Click to expand...

I suggest you remove the GPU to test and try and restore the original bootrom backup using Flashrom, but if the back-up file is bad you are going to have a problem, what software did you dump it with? If you PM me the dump and a good photo of the EEPROM chip and I’ll have a look.
 

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Well, it appears the HD 5670 in my 2010 iMac has died... Not to worry, I "fixed" it for free.
hd4670.png


Yes, that's the GPU from a 21.5" Late 2009 iMac in a Mid 2010 27". Seems like there is no bootscreen but brightness control works fine.
 
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