Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Status
The first post of this thread is a WikiPost and can be edited by anyone with the appropiate permissions. Your edits will be public.
Known issue with refind used with OC to show the picker, it does not update the name changes made during your configuration and sticks for all times with the first given name. Somewhere in the net somebody may have already found a solution or fix...

You can remove redundant, non-functional, or otherwise undesired entries in several ways, as described in the documentation:

http://www.rodsbooks.com/refind/configfile.html#hiding

Renaming entries is trickier. You have some control in the form of the name of the boot volume, which you can edit in most OSes. (rEFInd uses a filesystem label or, if that's not present, the GPT partition label. If neither is found, rEFInd uses a description, like "200 GiB ext4 volume.")

If you don't want to change the volume label or if you want to do more than this, your only option is to create a manual boot stanza:

http://www.rodsbooks.com/refind/configfile.html#stanzas

This is both a pain and tricky; a small error in the specification (like a typo) can cause the entry to fail to work, typically with a "file not found" error. IMHO, it's not worth the bother just to change the name shown in the menu; but of course you might disagree.

When setting up a new system I choose my volume (APFS container) names mostly like "Mojave", "Catalina", "Big Sur" etc...
Ok so I did install big sur from micropatcher everything works but I still don't get full brightness when I put slider on max for some reason it won't patch the backlight fix.
 
Hi all,
I have a A1312 / EMC2429 iMac with a Quadro K3000M 2GB (Dell 07RPRH) using the VBIOS from this thread.
My card shows 4GB VRAM instead of 2GB with the issues listed under known issues for this ROM.
Brightness control and bootscreen is working.
I can offer flashing test ROMs / beta ROMs (hotair rework station and serial programmer).
Can also provide org. Version 80.04.5A.00.01 BIOS of this card if needed for development/research.
 
  • Like
Reactions: BadBiscuit
I made a small app that fixes the color-depth issue at startup for some cards, like the 780M with @nikey22's ROM. After startup, start this app, the screen should turn black for a second and the colors/performance should be good to go. Appears to be working fine for me but obviously needs some testing first. Previously i had to put my iMac to sleep at least once or change screen resolution back and forth to fix this problem, now its a bit faster as i set it up in a way that it runs automatically on startup.

Download: https://github.com/passatgt/imac-color-depth-fix

Usage: just simply double click imaccolordepthfix to run. You can add it to your login items(system settings/users/login items), so it runs on a fresh startup automatically.
 
Last edited:
Tried to get my K3100M working a few weeks ago with some help from here but soon realised there was an issue with the mac itself I had to sort first.

Installed K3100M, have changed the BIOS chip as one on card was too small, have flashed with the new VBIOS, clean HS install. System now shows the bootloader screen and chimes but after the progress bar I just get a white screen. Any suggestions on what to try or do I give up, is this a sign the card is on the way out, have I missed something that has already been discussed other than the K3100Ms don't all work?
Have also tried with a K2000M and that's working fine in the system.
Thanks
 
** NVIDIA Quadro K3000M Mac Edition ROM **
Genuine Native Boot Screen & Brightness Control

Caveats post-install/Bugs:
- 4096MB? displayed instead of 2048MB reported by memvendorID {00 10 00 00}. Crashes when more than 2048MB is called upon by applications, full screen video playback. Looking into it, must set bios to read out Hex: 0800h instead of 1000h.
-16bit resolution glitch of UGA_DRAW_PROTOCOL - temporary solution: activate a sleep cycle
- WSON based bios chip. Clip rescue is not possible

With regards to the above 2Gb/4Gb issue - is there a simple fix that we can apply to the ROM - I don't micd having a go with the binary editor :)

The ROM is otherwise fantastic! I have three of these cards working on 2011 A1312s under Catalina & Big Sur, but they all crash - usually when someone plays video games. :)

Any pointers/tips welcomed ..

Chris
 
  • Like
Reactions: BadBiscuit
With regards to the above 2Gb/4Gb issue - is there a simple fix that we can apply to the ROM - I don't micd having a go with the binary editor :)

The ROM is otherwise fantastic! I have three of these cards working on 2011 A1312s under Catalina & Big Sur, but they all crash - usually when someone plays video games. :)

Any pointers/tips welcomed ..

Chris
There is no SIMPLE EASY fix. Give the developers time to work on that.
Don't harass them to work faster for your problem as in first post ;)
vBIOS editing, especially for Mac, is not an easy task, requiring multiple experimentation.
I am sure they are aware of the issue but there are more priorities to tackle than they can face.
When it is ready, it will be out.
Just be patient (not for COVID 🤪).
 
Tried to get my K3100M working a few weeks ago with some help from here but soon realised there was an issue with the mac itself I had to sort first.

Installed K3100M, have changed the BIOS chip as one on card was too small, have flashed with the new VBIOS, clean HS install. System now shows the bootloader screen and chimes but after the progress bar I just get a white screen. Any suggestions on what to try or do I give up, is this a sign the card is on the way out, have I missed something that has already been discussed other than the K3100Ms don't all work?
Have also tried with a K2000M and that's working fine in the system.
Thanks
Look to ur memory VRAM name, if you see H5GQ2H24BFR (BFR) bios downloaded its not supported to ur ram!
you need change strap resistor upper side ur card from 24,5Khom to 15,4Khom
this solution for K3100M with H5GQ2H24BFR memory.

this is bad things again from our bios maker.
 
I made a small app that fixes the color-depth issue at startup for some cards, like the 780M with @nikey22's ROM. After startup, start this app, the screen should turn black for a second and the colors/performance should be good to go. Appears to be working fine for me but obviously needs some testing first. Previously i had to put my iMac to sleep at least once or change screen resolution back and forth to fix this problem, now its a bit faster as i set it up in a way that it runs automatically on startup.

Download: https://github.com/passatgt/imac-color-depth-fix

Usage: just simply double click imaccolordepthfix to run. You can add it to your login items(system settings/users/login items), so it runs on a fresh startup automatically.
how to install? please step by step.
 
Preamble (Last Updated 12/01/2020 - Big Sur update)

This is not a plug and play solution!

You have probably found this thread because your iMac late 2009 to mid 2011 is having problems caused by the graphics card. It is well known that these graphic cards are problematic/defective. You will find websites that encourage "baking" the card. Without getting into the technicalities, it will work but this does not repair the graphics card. In fact, it only delays the problem. We have great news for you! You can install another graphics card that does not require much more effort. In addition, this will allow you to install more recent versions of MacOS. This thread has over 440 pages of useful information BUT the good news is all of that information has been summarized in this first post. It is HIGHLY recommended that you read through this post before asking questions. Then, reread the information. You will appreciate that the more experienced users cannot spoon-feed all new users. This distracts them from working on the files and tools that make all of this possible.

Before you post a question you may consider to add a signature to your account settings reflecting your machine type, graphics card, and possible even the problem you have. This signature sticks with every post you make and helps other to keep track and understand what is going on.

Enjoy!

This is the most important part of this process. The following information will help guide you in choosing your card. We have included the seven issues (see below: loss of brightness control, loss of boot screen, loss of target display mode, etc.) to overcome when installing a non-stock card into a 2009-2011 iMac. When choosing your replacement graphics card, you must take under consideration: your budget, your comfort level with doing modifications, your ability to live with unresolved issues, your computing needs, etc. Unfortunately, this thread cannot help you source cards as there are two many variables involved. Read through this information carefully in order to choose the best card for your needs.
  1. The modified (video) BIOS version made by @Nick [D]vB, @nikey22 and @internetzel require an Intel i3 CPU or better. There is currently no way to make the features of these VBIOS working on Core 2 Duo systems (27" Late 2009).
  2. Only Nvidia Kepler cards or AMD Ellesmere/Polaris cards will work in these iMacs. No other GPU variant has MacOS driver support. Both get full graphics acceleration with all current MacOS versions including Big Sur.
  3. Please do not harass the BIOS developers to go faster, release a particular BIOS, etc. Please do not clog up the thread with useless posts asking if your specific card will get a new BIOS. Ask not what this thread can do for you, but what you can do for this thread. It takes several months of reverse engineering and testing before getting a new BIOS working. It took only six years for the first really working card here on this thread! If you would like to use a different card, consider yourself in unknown territory. Of course, let us know if it works! Chances are that Kepler based cards will run using the right (most likely Dell) BIOS but will exhibit the seven problems listed below.
  4. There are two type and sizes of cards: Smaller MXM-A cards and bigger MXM-B cards running stable only in the 27" models. While all cards will function in a 21.5" model, they are unstable due to their high power draw. @highvoltage12v tested a 770M here and had frequent Kernel Panics in macOS and BSoD's in Windows. Do not try it!
  5. For all Nvidia MXM B cards and the WX7100 you need the MXM-B heat sink from the 27" mid 2011 model. This is the only sink with three heat pipes capable to get the generated heat by using 75W out of the system unter load.

CardBIOS linkBoot ScreenBrightness Control21.5/27/MXMHeat Sink Modperf
Quadro K610M +ROMyes (natively)yes (OpenCore)yes/yes/Aspecial install35%
Quadro K1100M +ROMyes (natively)yes (OpenCore)yes/yes/Ano65%
Quadro K2100M +ROMyes (natively)yes (OpenCore)yes/yes/Ano100%
Quadro K1000M *ROMyes (natively)noyes/yes/Ano35%
Quadro K2000M *ROMyes (natively)noyes/yes/Ano65%
Quadro K3000M ++ROMyes (natively)yes (natively)no/yes/Byes, 2 pipe100%
Quadro K3100M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe130%
Quadro K4100M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe180%
Quadro K5000M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe180%
Quadro K5100M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe200%
GTX 765M *ROMyes (natively)nono/yes/Byes, 3 pipe110%
GTX 770M *ROMyes (natively)nono/yes/Byes, 3 pipe150%
GTX 780M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe200%
GTX 880M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe150%
GTX 860M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe130%
GTX 870M ++ROMyes (natively)yes (natively)no/yes/Byes, 3 pipe?

The perf column reflects the OpenGL performance relatively to the original HD6790M (Unigine Valley).

*
BIOS by @Nick [D]vB that currently enable boot screens on your iMac, better performance, and BootCamp support.

**
Only Nvidia Kepler based cards work in iMacs. The K3000M has been used with High Sierra by @Roman78. Using OpenCore all these cards can have a limited boot screen functionality, now.

+
BIOS by @Nick [D]vB, and the Wizzard @nikey22 that currently enable boot screens on your iMac. Using OpenCore with these cards offers right now native brightness control, target display mode, UEFI Windows 10, and more! To enable backlight in UEFI Windows 10, see this post by @internetzel.

++
BIOS by Wizzard @nikey22, and @stephle for the K5000M that currently enable boot screens and native brightness control on your iMac. To enable brightness controls in UEFI Windows 10, see this post and this more recent post. Only the audio support with UEFI Windows 10 would make OpenCore necessary.
These cards will run in a Late 2009 system, but all face (only there) another issue. After a PRAM reset the LCD remains black.
Fair warning:
There are K3100M, GTX780M (and possibly more type of) cards available on the grey market not working with the BIOS published and there are K3000M cards available not posting in some of the 2011 system. We cannot identify these in advance. Reason unknown. Other modifications like WiFi/BT or USB3 upgrades may interfere with the new GPU and destabilise the system. A "boot chime loop", i.e. non booting system is the final result.

CardBIOS linkBoot ScreenBrightness Control21.5/27/MXMHeat Sink Modperf
AMD WX4130 +++ROMyes (OpenCore)yes (natively)yes/yes/Aspecial install130%
AMD WX4150 +++ROMyes (OpenCore)yes (natively)yes/yes/Aspecial install130%
AMD WX4170 +++ROMyes (OpenCore)yes (natively)no/yes/Byes or no?, 3 pipe150%
AMD WX7100 +++ROMyes (OpenCore)yes (natively)no/yes/Byes or no?, 3 pipe230%

The perf column reflects the OpenGL performance relatively to the original HD6790M (Unigine Valley).


+++ These AMD Polaris cards are much more modern, but are difficult to source. Check the online offers carefully (the differences are explained below). With custom BIOS and OpenCore, these are very compatible and offer native brightness control, boot screens, UEFI Windows 10, and much more modern capabilities and future-proofing than the NVIDIA cards. They also allow for 4K H.264, and huge 4K HEVC decode/encode gains in production. There are still some problems to solve. Although SideCar will not work with these modern cards.

Using the GOP BIOS (links within the table above) you will have native brightness and and get an emulated boot selection only with OpenCore. OpenCore enables 4K H.264, and huge 4K HEVC decode/encode by using the iMacPro1,1 ID. This hack makes your iMac look alike a new machine and gives you similar features.

Using the EG BIOS version you will get a native Apple boot picker with an iMac firmware modification on an additional external display, only. These BIOS versions offer native brightness control, too. Without OpenCore you can have 4K H.264 with a modified AppleGVA.framework but no 4k HEVC. You can also use the same OpenCore setup as with the GOP BIOS versions and combine the best from both worlds. Here you will find new EG BIOS versions for the WX4xxxx line. Both solutions have their own advantages.
  1. AMD WX7100 (recognized as Radeon RX 580 in macOS)
    It is important to identify the card. This card has been unpredictable. @Nick [D]vB has obviously a working card with number 109-C95847-00C_02. @Pascal Baillargeau has a card working with number 109-C95847-00D_02. However, other users have not been successful with the same exact models. For example, @Vego17 recently got the same card as @Nick [D]vB. But his card did not work in his iMac 2011 while it does run normally in a Dell Precision 7710 laptop.
  2. AMD WX4170 (recognized as Radeon RX 560 in macOS)
    Some come with a blank EEPROM and are missing a resistor. Working models with EEPROM are scarce. User @jborko did a write up HERE on his experience installing a WX4170. You can use the 4GB version of the latest WX4150 rom too (refer to the table at the beginning).
  3. AMD WX4130/WX4150 (recognized as Radeon RX 460 or RX560 depending on used BIOS in macOS) - currently 09/10 Only
    This card needs to have an EEPROM chip on board too. There are multiple versions of this card - only the "Dell" branded versions currently work. These WX 4130/4150 are not detected in every case by the 2011 iMacs for unknown reason, and therefore are currently not fully compatible. Even worse, some models are not detected in any iMac model from late 2009 to mid 2011. A few Dell versions will be recognized and run in 2011 models. There is currently no rule available to figure out in advance which model will run. Same situations as with the WX7100.

A: Not necessarily. This is not a plug and play solution! This "fix" is more of a "mod" to revive our iMacs. Depending on your scenario, it will require a full iMac disassembly, knowledge of BIOS flashing, dremel tools, heatsink modification, careful handling of logic board components, system administration at a higher level and some Unix or terminal command line awareness. With the used/grey market for many of these cards, other issues may pop up as well. Please inform yourself before undertaking this process.
A: Your MXM card is likely running an incompatible BIOS and will need to be flashed with the correct one. This can be done from within Windows or Linux using NVFlash, or with a CH341a programmer.
A: BIOS can be flashed in one of two ways: Either directly with a CH341a clip programmer or with the NVFLASH or AMDVBFLASH software in Windows or Linux. Only most AMD cards and K610M, K1000M and K2100M cards can be used with the clip. All other NVIDIA cards have so called WSON BIOS packages. Experienced users may solder a different BIOS chip onto those cards to be used with a clip, too. You can use the flashrom software with the clip directly from the MacOS terminal following this installation guide.

AMD flash software and NVIDIA flash software is only available on Windows and Linux.

User @xanderon created a pre-made USB that can flash Nvidia cards in the iMac with Linux over SSH. Many have found this the easiest method. There is an add-on to flash AMD cards using this method, too.

Additionally, user @jowaju created a simple Installer package that can be run on macOS Sierra (10.12) and higher that creates a 15GB Windows 7 Bootcamp partition with all the needed tools.

THIS external POST helps describes the flashing process. Others have found THIS POST useful.

Do a PRAM reset after flashing if you cannot boot into a known to work MacOS version!
A: No - all cards outlined in this guide use the included NVIDIA drivers in macOS. No additional GPU drivers are needed.
A: A lot of people here have tested Maxwell cards with their 2011 iMacs, and have had various issues from no internal display, no backlight on internal display and the card not hitting boost. Additionally, macOS Mojave (10.14) deprecated support for the NVIDIA Web Drivers which allowed the use of Maxwell and Pascal cards. For now, Kepler GPUs and the experimental Radeon cards seem to be our path forward.
A: Yes! So far, the K1100M & GTX 770M have been tested firsthand and successfully provide 4K@60Hz output via mDP to DP adapter on a 4K display. Others should work just as well.
A: For the GPU Die any thermal Paste like Thermal Grizzly’s Kryonaut paste is good for the Die. For onboard components, many recommend using K5 Pro Viscous paste instead of thermal pads, due to the unevenness of the heatsink, it’s also similar to Apple’s original Design. You can get it from the Bay or from the Book Store, too.
A: We are still aggregating GPU benchmarks. There is a special section on this page and we added to the GPU tables a relative (to the old flagship HD6970) performance column only based on the the OpenGL benchmark.
A: For an MXM-A swap (the shorter/less power draw cards) there are no modifications that are needed for the heatsink on both the 21.5" and 27" model iMacs. The X-clamp still needs be removed from the back of the card and have the screw posts drilled or tapped out in order to fit the heatsink's screws. Separate the X-Clamp using a hair dryer before drilling or tapping - it is just glued to the board. Skipping this step can fry or damage your card. If you've cleaned your heatsink, be sure to re-apply thermal pads around the GPU VRAM to prevent contact with the bare metal of the heatsink. Use electrical tape to isolate card components from the sink! Watch closely after installing the card. Take a look at the attached pictures of this post!
A: The MXM-B cards only work on the 27" models due to power restrictions. There is one additional mod needed to make the MXM-B card fit. First you must grind down your heatsink in the area where one or two large coils sit, this way the card will sit flush with the heatsink. You must prepare the the X-clamp in the same way as described with MXM-A cards above. Take a look at the attached pictures of this post!
Some cards may work with the bigger MXM-B heat sinks with 2 copper pipes from the 2009 and 2010 models due to limited power draw. The WX4170 with a TPD of 50W is, the K3000M and K3100M may be such a candidate. The HD 5850M is listed with 40W-60W power draw.
If you have a 2 pipe heatsink that came with the lower end GPUs on these iMacs and want to use an MXM-B Card, you'll have to buy a 3 pipe heatsink to cool cards properly. You can get these on eBay.
A: Most likely the installation of card on the heat sink caused a short, or the card is simply faulty, or the card has not been reseated in the slot properly, check all this out first. Any hardware issue has to be solved by yourself!
A: We all know that none of the modifies BIOS versions for the Metal GPUs listed in the table above is able to provide the internal GPU temperature back correctly to by used by the iMacs internal Apple SMC software to control the (ODD) fan according to the GPU internal temperature. To address this issue we recommended strongly to use a free software called Macs Fan Control. But you can also try to solve this problem by using the ODD temp sensor.
A: The first term simply describes the fact that you can use GUI related operations like moving, resizing, closing an application or Finder window fast and smooth. This has been a serious issue with all patched installations of macOS versions on unsupported hardware. All "metal" cards listed above offer full graphics acceleration. Especially with Big Sur this has become more important since only "metal" enabled cards offer now the full graphics acceleration. The term video acceleration describes the hardware abilities of the GPU supported by the macOS. Only the new AMD GPUs offer 4K HEVC and 4K H.264 if installed in an iMac. If you want to know more about the possibilities AMD cards offer watch some of the videos collected here.
A: First, read the full thread. Staying on top of the progress here is key! Currently we have released a series of BIOS versions for Nvidia GPU which do not need any hardware modifications, only some patched software. But there have been backlight mods created to be used with AMD and Nvidia BIOS versions which do not offer native backlight control. And of course every user may help sharing his knowledge to new users - but please stay on topic. This is not the thread of everything related to these old iMacs :)

This software is needed for Nvidia K610M, K1100M and K2100M to get native brightness control and for all AMD cards using the GOP or EFI BIOS getting a boot screen emulation and enabling 4k HEVC and 4K H.264 GPU acceleration and finally for all users of iMac 11,x systems to install and run Big Sur. It became a main part of this development, ignoring or denying does not help. You will not get the features described above without using OpenCore.

Benefits!

  1. Brightness control with K610M, K1100M and K2100M cards
  2. AMD Video acceleration 4K HEVC and 4K H.264
  3. Emulated boot picker for all systems using AMD cards!
  4. Big Sur for 27" Late 2009 and 21.5" and 27" Mid 2010 iMac models

Need to be done in advance?

  1. Install the lastest Apple firmware for your iMac. This can be done by doing a fresh High Sierra including all published Apple updates first on an internal disk before you can use the Catalina Loader or Mojave or Catalina or Big Sur.
  2. Before starting this use the RomTool and it's password (rom) from this site and backup your upgraded iMac EFI firmware and save it to an external storage device.

This High Sierra update will install a file called "Firmware.scap" to the (invisible) EFI partition of your internal iMac drive and during the next reboot(s) (of this disk) this EFI update will be applied. This takes some time in the dark (if your GPU BIOS has no working EFI boot screen to show the progress bar) , a loud beep may be heard and another reboot is coming.

What is OpenCore / Catalina Loader?

When we use the phrase Catalina Loader and OpenCore at the same time it is because the Catalina Loader is a piece of software using OpenCore.

Where to get it?

Just download the
latest image and fitting OC EFI folder and install on an SD card or USB memory them drive, 1GB space will be sufficient. You will find a short documentation attached to the post. You just need to rename the config.plist file in the EFI/OC folder on the SD card according to your GPU. Follow this docs attached at the post linked above.

More Information:

If you want to know what happens behind the curtain please read the original OpenCore post for more info. @herrdude provided an additional guide, another longer one by @Ausdauersportler and others named "Using Catalina Loader on an iMac" focussing on the special needs of 2011 models and special settings for AMD cards. All guides are worth reading before starting the installation.

More details about OpenCore on Legacy Apple hardware is available on this thread. The MacPro users basically explored the same things about Activate AMD hardware acceleration. Finally you may also study the OpenCore docs.

Using older MacOS versions (supported)

According to this list the Nvidia drivers are part of macOS since 10.8.3. You might check this out on your own. At least on recent successful upgrade of an iMac 12,2 with macOS 10.10 can be reported here.

Installing MacOS Sierra (supported)

Supported MacOS version can be installed using the original Apple installer. To avoid the black screen issue install this package.

Installing MacOS High Sierra (supported)

Supported MacOS version can be installed using the original Apple installer. To avoid the black screen issue install this package.

Installing this last supported macOS version brings in the latest firmware. There will be unlikely ever new firmware versions since High Sierra went out of Apple support these days.

Installing MacOS Mojave (unsupported)

The recommended method is to have High Sierra as your primary OS and install Mojave alongside on a separate partitions or APFS container partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues. High Sierra offers a working recovery partition, too.

This is a two step installation. First you will use the @dosdude1 patcher and later install a package needed to address the hardware changes you made by changing the GPU.

1. You could preinstall Mojave before changing your GPU. Use dosdude1's Mojave patcher to do the install.

Important: While running the Post Install tool, make sure you deselect the Legacy Video Card patch option (since you will using a new, compatible metal graphics card).

2. GPU and machine related patches: (see next section common macOS problems)

Late 2009, Mid 2010: To avoid the black screen issue install this package or follow instructions this post.
Mid 2011: Install this package to avoid sleep problems, black screen etc. or follow this post.

Installing MacOS Catalina (unsupported)

The recommended method is to have High Sierra as your primary OS and install Catalina alongside on a separate partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues.

This is a two step installation. First you will use the @dosdude1 patcher and later install a package needed to address the hardware changes you made by changing the GPU.

Important: Post-install patching has changed since Mojave.
Patching is now automated if your SMBIOS is detected to be an unsupported machine. Currently, only the 2011 iMacs have the "Legacy Video Card Patch" disabled by default. You will avoid this patch (since you will use a new, compatible metal graphics card) and will need to modify a plist file if you are using a 2009/2010 iMac with a Metal compatible video card or more easily while building the patcher, you can go to the "Options" menu and de-select "Auto-Apply Post-Install Patches" to avoid this.

Important: While running the Post Install tool, make sure you deselect the Legacy Video Card patch option (since you will using a new, compatible metal graphics card).


1. The process for Catalina is similar to Mojave as mentioned above. Use dosdude1's Catalina patcher to do the installation.

2. GPU and machine related patches:
Late 2009, Mid 2010: To avoid the black screen issue install this package or follow instructions this post.
Mid 2011: Install this package to avoid sleep problems, black screen etc. or follow this post.

See next section to manually fix this issue if you have accidentally installed this patch. Best option is reinstalling Catalina from the scratch!!

Installing MacOS Big Sur (Release 11.0.1 20B2029) (unsupported)

The recommended method is to have High Sierra as your primary OS and install Big Sur alongside on a separate partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues.

Having a Metal GPU makes your iMac Late 2009, Mid 2010, Mid 2011 Big Sur compatible. To make the package perfect and nearly fully compatible you could have installed an WiFi/BT upgrade, but it is not necessary to install and run Big Sur. The stock old Atheros WiFi card will be supported.

We managed to get all necessary patches for all iMac hardware to be included in the current state of the art Big Sur patcher (the iMac fork of the @Barry K. Nathan micro patcher). There will be no manually installation of more extensions as with Mojave and Catalina, before. To understand the installation and patching process please follow the instructions provided on the Github download page step by step! The patcher will auto detect the installed GPU.

To avoid a kernel panic on boot of the Big Sur installer all users of the 2009 and 2010 iMac systems will have to use a special OpenCore based solution, to understanding the reason please read this post. This applies to all Kepler cards used, too. The most easy way will be to use the Catalina Loader provided here. There will be an update to the Catalina Loader using OC 0.6.3 including this patch, too. Check this post about the process of installation and normal boot of Big Sur using OpenCore.

Please keep in mind that the development is still ongoing and the developers on the thread cannot really support you with installation issues right now. You need MacOS and UNIX experience with the Terminal app and the command line to accomplish this task.

Notes:
  1. The stock WiFi and BT works properly patched, too. No HandOff and no Continuity, of course.
  2. AMD based systems offer 4K H.264 and 4K HEVC with Big Sur, again.
  3. Nvidia based systems lack currently still of iGPU based H.264 acceleration.
  4. Since all iMac 11,x models will need an OpenCore (OC) solution with Big Sur we have now only a few systems remaining working without OC, the iMac 12,2 using NVIDIA cards marked with a ++ in the table above. Due to this fact all systems using OC will have to use the Catalina Loader (CL) and the attached 0.6.3 (or later) EFI folders. These are preconfigured to inject all other extensions needed like Lilu, WhateverGreen, AppleBacklightFixup, PolarisBoost etc.
  5. All ++ card users with iMac11,x will need the special version of the AppleBacklighFixup.kext published here on the CL. It is the same link as in the table above. Please just replace the file on the CL in the EFI/OC/Kexts folder if and only if you experience any oddity with the backlight control.

After every MacOS update you will have to do the patching explained here to avoid common problems. Installing kernel extensions to the system is not an easy task. A complete installation guide to do this has been published (see link below with Q2).

Q1: I get a black or blank screen on boot, how to fix?

A: Sierra and later has been causing "black screen" issues for many folks. This is caused by a lack of kext initialization due to a lacking board-id in the AppleGraphicsControl.kext (short AGC). A patched AGC kext and a further explanation can be found HERE, thanks to @highvoltage12v. Please look and the next question and link to get the installation guide, needed. Using some Nvidia cards in late 2009 iMac causes extra pain. The internal LCD will come up only after installing the patched AGC and booting into the newly patched MacOS. The BIOS versions will need a fix to come around this additional problem.

Q2: Sleep is broken and QuickSync is not working on my iMac 2011 in Mojave and Catalina, how do I fix this?

A
: Solution for Mojave and Catalina, the SandyBridge kexts are missing. Installing them fixes sleep, but causes extended boot times. @highvoltage12v has provided the needed patches containing the SandyBridge kexts in THIS POST which can be installed. You can also simply install this Catalina package or this Mojave package.

Q3: After installing Catalina on my Late 2009/2010 iMac my animations are broken/choppy, the Dock is grey and the menu bar isn't translucent. How do I fix this?

A: The dosude1 installer unfortunately automatically executes the "Legacy Video Card Patch" leaving Late 09/2010 MXM swapped users with broken/choppy animations. If you did install Catalina and would like to manually reinstall the stock Kexts and Frameworks, a guide has been written by @highvoltage12v to manually overwrite the patched files with stock files. Another fix is the reinstallation of Catalina with auto-patching disabled. It turns out to be the less error prone solution.

You may face all kind of hardware problems after assembling your iMac again. There is an incomplete list of common (hardware) problems including the links to the original Apple iMac Technician Guides to trouble shoot such problems.

Some other possible modifications as USB3 or WiFi/BT 4.x replacements may interfere with a new GPU.

Please understand that we cannot remotely repair or identify broken hardware. And there is no proof possible that hardware is broken. Do not ask for one. You may likely buy a dead used card. Check it before! This is not the "repair my iMac help desk thread".

Why do I find the plan at the very end of this post? Because the steps listed are described in more detail in the former sections. This plan is not complete and because we have five different iMac systems with different architectures, three different MacOS versions, nearly 20 graphics cards in mainly 5 flavours, we cannot make a simple single plan:
  1. choose a GPU, get the card (we do not comment on sellers)
  2. optional: get an SD card / USB this drive and prepare it with the Catalina Loader in advance if needed by the GPU
  3. upgrade your iMac boot rom firmware to the latest version (mandatory) by installing High Sierra on an internal disk including all recent Apple upgrades!
  4. using RomTool (password rom) dump your iMac firmware and store it externally (highly recommended)
  5. optional: get a CH341A clip programmer and install flashrom using brew on another Mac
  6. optional: apply the EG mod to your iMac firmware and restore the modified image using a CH341A clip
  7. optional: get an SD card / USB this drive and prepare it with the Linux flash utility, grab the most recent BIOS of your card of choice and copy it directly to the folder named flash on that drive
  8. get the most recent BIOS version following the links in the table above, flash the card using a clip programmer in advance or install the card and use the flash software tools (mandatory)
  9. relocate the ODD temperature sensor and install the card
  10. check the basic functionality with the latest supported OS which is High Sierra (highly recommended)
  11. install Macs Fan Control to and control the ODD fan according to the GPU heat sink temp sensor (mandatory)
  12. apply basic patches like the AGC if you experience a black screen (see above)
  13. optional: use the Catalina Loader (if needed by the card)
  14. make load test (UNIGINE valley and Geekbench5 metal) and submit results (see above)
  15. get used to the tools and patches, especially with OpenCore and Macs Fan Control
  16. move on to Mojave or Catalina using the @dosdude1 patcher (details see above)
  17. optional: apply sleep patches if using the 2011 iMac (Mojave and Catalina, only. see above)
  18. optional: install iGPU framework if using the 2011 iMac (Mojave and Catalina, only. see above)
Whenever you have problems come back to this post and read the guides. There have been hundreds of successful installations during the last year. If you experience hardware problems you have to solve these on your own.

This is a wide open field.

1. OpenGL

Historically MacOS used and supported and still supports with Big Sur OpenGL. To measure the performance of an GPU we currently use the free Unigine Valley benchmark suite. To use it please use the following settings standard resolution of 1920x1080, quality Medium, stereo 3D disabled, Anti-aliasing Off otherwise results cannot be compared. The software will run on any macOS version since Sierra and on Windows, but there it is using the Microsoft DirectX implementation and results cannot be compared, again.

2. Metal

Metal is the new sugar for GPU addicts, it has been introduced in 2012 hardware (HD4000 and NVidia GPU) in Apple hardware. During the last months we used GeekBench5 Metal. Lately we discovered a new more stable and hopefully more meaningful MetalBench software, which will run only on Catalina and later.

Table of Benchmark Software and upload and result forms


Using a non Apple Card within an iMac creates these problems. Some have been solved with the published custom BIOS versions, others not. Especially the problem 7 has not really been solved and needs a software solution or th relocation and reuse of the ODD temp sensor.
  1. The loss of EFI boot screen;
  2. The loss of backlight control;
  3. You can only connect one external monitor to 27" iMacs;
  4. The loss of Target Disk Mode;
  5. The loss of Target Display Mode (TDM);
  6. The loss of running the built-in Apple Hardware Test (AHT);
  7. The loss of temperature sensors on the new GPU. But there is a solution!
1. Boot Screens are now available on all listed cards using custom VBIOS and/or OpenCore

You may use the OpenCore booter to add a boot screen feature to every card - even the Nvidia and AMD cards not listed here or known to have no BIOS support to show the original apple boot picker. There is a small delay between the chime (POST) and the initialization of the actual boot screen on the current NVIDIA modded BIOS. Most of the time (such as a quick reboot in macOS) the system boots too quickly for the EFI portion of the BIOS to initialize, making it appear that you may not have a "boot screen." All is working as intended if you can hold the "Option" key at startup and get a boot picker.

2. Native Brightness control is available for cards marked with + or ++ using a combination of custom BIOS and OpenCore.

For other cards, brightness control may be added in the future. Be aware that without brightness control, the iMac display runs at full brightness by default. For higher powered cards and 27" models, this can generate a lot of heat.

If you would like to "dim" your display using color dimming, many have used the app Brightness Slider, which is available on the App Store for free.
You can also use this app, which works better than most apps in the App Store, because it will dim the colors on the whole screen and it will display the built-in OSD, just like native brightness control.

Additionally, hardware level modifications using a DyingLight module or a Raspberry Pi have been used for brightness control. This software written by @passatgt can be run on a Pi for backlight control. Another hardware solution can be found here.

Nvidia cards marked with ++ with native brightness control may notice their displays are not hitting maximum brightness control Potential. A kext modified by @highvoltage12v can be found here to fix this issue.

Last, but not least: User @Lottosmp came up with a solution based on the former engineering.

3. Despite having 2 miniDisplayPort outputs, the 27" 2011 iMac will only output to one external display. There is currently no fix or workaround for this.

4. Target Disk Mode is available on all cards marked with a + or ++!

5. Target Display Mode (TDM) is available on for cards marked with + when using both custom BIOS and OpenCore. Target Display Mode is *only* stable under High Sierra and should not be used in later OS's.

6. Apple Hardware Test (AHT): There is currently no fix for running the internal service diagnostics. You may search the net for the ASD (Apple Service Diagnostic) package instead. For each system there is a different package. Download and install the package onto a SD card or a DVD, which will give you full functionality. A working download link may be hard to find. It is not open source.

7. GPU Temperature Monitoring is available on cards marked with a + or ++when using both custom VBIOS and OpenCore. A modified version of FakeSMC and GPUSensors is included with the OpenCore bundle to allow monitoring of GPU temps. But you still have to use some third party tool to control the fans. The GPU die temperature is not available and (probably for that reason) the Apple SMC still not running properly. Check the PDF attached to this post for details. But you may also relocate the ODD sensor as described in this solution! The ODD sensor will drive the fan up.

~~~~~~~~~~

Original Post from @MichaelDT June 14th, 2013.

I will be attempting to upgrade the MXM card in my 2011 21.5 iMac from the factory 6770m 512mb to a NVidia 675m 2GB. I choose this card because the chipset already has support from 10.8.3 onwards and affordability for an experiment. I am hoping that it will work without flashing like many of the other non MXM modern graphics cards (UEFI support) do in 64bit EFI Mac Pros ( I may loose the initial boot screen). But if all else fails I will attempt a flash. I will report back my findings when the card arrives (from Hong Kong). Wish me luck hopefully this will give those of us with the last modular iMac a path forward.
Hello community,

About two months ago the graphics card of my iMac mid2011 A1312 broke. After much Google time I came across this forum and ordered a GTX765M (Alienware branding) from Ali .... x. I have now installed this, I have not yet connected the panel because I wanted to boot up with the LINUX USB boot stick offered here in the forum. Now I have the problem that the computer does not seem to boot from the stick (all hard drives are disconnected) because it does not appear in the router's listing. There are two diagnosis LEDs on (LED 1 and 2) ... I wanted to flash the BIOS of the graphics card with the USB boot stick. Has anyone already had the problem and has a solution?

<UPDATE 20201202>
The heatframe is milled off at the appropriate points and the individual components on the edge of the board, which are significantly higher than all the others, are insulated with pads. The boot gong comes as normal and it also looks like it is booting from the stick, at least it flashes.
</UPDATE>


Thank you

Pete
 
Last edited:
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
how to install? please step by step.

Click the green Code button and select Download ZIP. Extract and double click imaccolordepthfix. If it says its from an unidentified developer, go to System Preferences / Security & Privacy and click Open Anyway.

If it starts and looks ok, go to System Preferences / Users & Groups / Login Items and add the imaccolordepthfix file to the login items, so it will run on startup.
 
There is no SIMPLE EASY fix. Give the developers time to work on that.
Don't harass them to work faster for your problem as in first post ;)
vBIOS editing, especially for Mac, is not an easy task, requiring multiple experimentation.
I am sure they are aware of the issue but there are more priorities to tackle than they can face.
When it is ready, it will be out.
Just be patient (not for COVID 🤪).
Apologies - perhaps
I wasn't harassing anybody.
I simply asked if anyone here knew of a fix that could be applied, as hinted in "Looking into it, must set bios to read out Hex: 0800h instead of 1000h."
I have endless patience
Chris
 
I have i big issue and i hope u can help me , i'v repleced my card with a k2100m ( iMac 2011 21.5") but when i try to turn it on i have the boot-chime-loop issue...Black screen and start sound avery 8 seconds.. is there any way to fix it? I'v tried the method described in the "known issues" but it didn't work. I'v tried to tear down the gpu again and double check everything but no progress. I still have the 503 led off and this boot-chime-loop issue. The only thing that i noticed is that when i hold "Alt "down as for going into the boot menu , it stops ( sorry for grammatic errors, i hope u understand anyway)
 
Look to ur memory VRAM name, if you see H5GQ2H24BFR (BFR) bios downloaded its not supported to ur ram!
you need change strap resistor upper side ur card from 24,5Khom to 15,4Khom
this solution for K3100M with H5GQ2H24BFR memory.

this is bad things again from our bios maker.
Memory on my K3100M is H5GC2H24BFR chips, which is a lower bandwidth and voltage chip than H5GQ2H24BFR
 
Look to ur memory VRAM name, if you see H5GQ2H24BFR (BFR) bios downloaded its not supported to ur ram!
you need change strap resistor upper side ur card from 24,5Khom to 15,4Khom
this solution for K3100M with H5GQ2H24BFR memory.

this is bad things again from our bios maker.

Insulting the BIOS maker and seeking for a step by step guide within minutes - how bad was the education you got? It is people like YOU driving people like me out of this project.

At least you serve as an interesting example of another opportunistic human being - something we possibly need once in a while. Either you leave this thread or you start to be thankful and more polite for all the free work others did for your.

To all others:

There is always the possibility to ignore posts of certain user completely - just move the mouse pointer over the name of the user and press ignore! I did this for this user here here after his third identical post begging for a K3000M BIOS for free, of course.
 
I have i big issue and i hope u can help me , i'v repleced my card with a k2100m ( iMac 2011 21.5") but when i try to turn it on i have the boot-chime-loop issue...Black screen and start sound avery 8 seconds.. is there any way to fix it? I'v tried the method described in the "known issues" but it didn't work. I'v tried to tear down the gpu again and double check everything but no progress. I still have the 503 led off and this boot-chime-loop issue. The only thing that i noticed is that when i hold "Alt "down as for going into the boot menu , it stops ( sorry for grammatic errors, i hope u understand anyway)

Do you have partially insulated tape between Heatsink and Video Card ?
That seems like short circuit between heatsink and card / or faulty card.
Do you patch with CH341A / detect MXIC / verify ?

NVIDIA KEPLER.jpg
 
Last edited:
  • Like
Reactions: Ausdauersportler
Do you have partially insulated tape between Heatsink and Video Card ?
That seems like short circuit between heatsink and card / or faulty card.
Do you patch with CH341A / detect MXIC / verify ?
Yes i've done it . the gpu is"stock" , i bought it as new to aliexpress as a dell model , i've just put it into the machine . My purpose was to flash it with windows nvflash , but i can't 😣
 
Last edited:
  • Like
Reactions: Ausdauersportler
Recommended to use a USB Programmer CH341A which U can find on ebay:

https://www.ebay.com/itm/EEPROM-BIO...247642?hash=item3da242201a:g:JlYAAOSwpSlekDy~

Perhaps try to get it in your country for less...

View attachment 1685049
...there is a HP8300 WIN10 PC behind this picture, no iMac !

Thank you for ur answers , the problem now is that i don't know how to use it , i'm a novice in this " world " and i don't know if i'll be able to do this ... i'm really unlucky 😩
 
Thank you for ur answers , the problem now is that i don't know how to use it , i'm a novice in this " world " and i don't know if i'll be able to do this ... i'm really unlucky 😩
It gets easier after the first one. :).

Most folks that are not intimidated by tearing down an iMac to swap a card are up to the task. That said, you might find someone close to you, who can flash it for you. Where are you located? Since the clip method does not require an installation to flash, it is literally a 30 second task to do one, once you are setup and comfortable with the process.
 
It gets easier after the first one. :).

Most folks that are not intimidated by tearing down an iMac to swap a card are up to the task. That said, you might find someone close to you, who can flash it for you. Where are you located? Since the clip method does not require an installation to flash, it is literally a 30 second task to do one, once you are setup and comfortable with the process.
I've seen a video in the forum that shows how to use the CH341A and i think that i can do that. I'm from italy so it's not much easy for me to understand everything and i don't know if there is someone near me that had already done it . But i won't give up. I'v ordered now a CH341A from amazon , it will arrive tomorrow , i hope i'll be good enough to do this ( tearing down iMacs , iPhones and Laptops are enough easy to me but i'm not so expert with software programs hahahahaha) fingers crossed 🤞🏻 😊
 
Last edited:
  • Like
Reactions: BadBiscuit
There is no SIMPLE EASY fix. Give the developers time to work on that.
Don't harass them to work faster for your problem as in first post ;)
vBIOS editing, especially for Mac, is not an easy task, requiring multiple experimentation.
I am sure they are aware of the issue but there are more priorities to tackle than they can face.
When it is ready, it will be out.
Just be patient (not for COVID 🤪).
@KennyW, I agree with your call for patience.

I also appreciate @christberry's remarks about crashes while playing full screen games. I find the same when running a full screen music video on iTunes with latest K3000M bios. It will play but often crash upon close. It is good to know the ramifications of the "4G bug" as a real world limitation. Some may be willing to live with that, but others may not, and would be advised to steer clear for the time being.

The K3000M is available either 2G and 4G populated; Does anyone know if the bios has been tried successfully on a 4G card, and if in that case this memory size issue is not a factor? I assume so, but don't recall seeing that stated. I got my 2G card for $40, but might have paid a premium to get one with 4G to achieve stability.
 
I've seen a video in the forum that shows how to use the CH341A and i think that i can do that. I'm from italy so it's not to easy for me to understand everything and i don't know if there is someone near me that had already done it . But i won't give up. I'v ordered now a CH341A from amazon , it will arrive tomorrow , i hope i'll be good enough to do this ( tearing down iMacs , iPhones and Laptops are enough easy to me but i'm not so expert with software programs hahahahaha) fingers crossed 🤞🏻 😊
In the first post, there are directions on the various ways to flash the BIOS.
There are also many videos in YouTube teaching how to use the ch341a programmer.
I also started to learn this few months ago as a newbie. :)

The Linux USB flash drive is really the easiest but you need another computer for remote SSH via ethernet connection.
The problem with the ch341a programmer lies more often in getting a good clip to clamp on the BiOS chip securely and correctly without burning it. Some BIOS chips (e.g. win-bond type) cannot be flashed easily in this way, especially the nVidia Quadra Kxxxx series GPU. You also need to install brew and flashrom via Terminal for the flashing if you don't have Windows via BootCamp installed in your iMac or another Windows PC. I am not sure whether the flashing is possible if running from a Virtual Machine of Windows in Mac. Thus, I feel it is more demanding in setup with the clip method but once you have got everything up and try it, it could be more convenient than the Linux method.
 
Last edited:
In the first post, there are directions on the various ways to flash the BIOS.
There are also many videos in YouTube teaching how to use the ch341a programmer.
I also started to learn this few months ago as a newbie. :)

The Linux USB flash drive is really the easiest but you need another computer for remote SSH via ethernet connection.
The problem with the ch341a programmer lies more often in getting a good clip to clamp on the BiOS chip securely and correctly without burning it. Some BIOS chips of win-bond type cannot be flashed easily in this way, especially the nVidia Quadra Kxxxx series GPU. You also need to install brew and flashrom via Terminal for the flashing if you don't have Windows via BootCamp installed in your iMac or another Windows PC. I am not sure whether the flashing is possible if running from a Virtual Machine of Windows in Mac. Thus, I feel it is more demanding with the clip method but once you have got everything up and try it, it could be more convenient than the Linux method.
I think that i'm going to use windows but i didn't know that there is this problem with the kxxxx GPU . I'm going to flash it with another desktop pc with windows that i already have , but just to be clear , the process is different from the youtube video linked in the thread? could i burn the bios chip?🥶😱
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.