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About AirPlay on Big Sur and Monterey:

This is an ongoing project. AirPlay sound is working even to my 13 year old AirPort Express station and to my recent 4K AppleTV. The image will not be displayed (unlike with Catalina on this system with this AMD GCN).

Q: Who can share AirPlay experiences with AMD cards and on Big Sur or Monterey?


View attachment 1874938
Here my experience with Big Sur/Monterey and Airport on an iMac 12.2 with AMD WX4150:
Could only play sound via AirPlay using the Music App. And only if an Airplay 1 device was in the connected mix the iMac also connected to Airplay 2 devices like a Marantz amplifier, latest firmware updated airport express, Sonos speaker, AppleTV 4. No video streaming via Airplay was possible.
For those who do not have have an Apple Airplay 1 device like Apple TV2 or a (not firmware updated) airport express, you can also use a Kodi box running Libreelec (in my case an Intel Nuc) as Airplay 1 device.
So I decided back to go back to Catalina+OCLP. The machine runs flawless now with full AirPlay 1 and 2 Audio/Video capabilities. SIP and SMB enabled.
Cheers
 
Yes, you really need a very good reason for me to create VBIOSes that support Boot Camp. Apple's Boot Camp uses legacy BIOS booting, but our unsupported Macs in fact get better Windows driver support by using OpenCore and doing an UEFI installation of Windows.
Ok. In that case, I will go for OCLP and windows in another drive. THanks.
 
Agreed. EFI is so powerful that it's easy to put the driver anywhere and load it. Maybe having the driver on the GPU makes it load earlier which removes the need to fix up stuff later.

Driver#### happens before the Apple Startup Manager starts. It's probably the same for Target Disk Mode. So at least it's earlier than all the stuff you might want to do at startup (at least all the UI bits that the user can interact with).
Hi, again!

Just thought moving over to this thread would minimize the risk of getting punished for posting more off-topic posts.

Basically I used the USB3 drivers test as a proof of concept to achieve the same thing @internetzel asked for last summer. During vBIOS development the most time will be wasted into the recovery from bad flashes. Our main goal is getting the EFI Boot picker working on AMD cards and each time I do another test the risk of getting a brick is not zero.

So your Driver#### method is the only solution acting early enough to test new vBIOS versions. Unfortunately I got no single successful load during the last days. Before trying the USB3 stack I was using vBIOS drivers.

Do you have a simple must load efi driver to check if this method is still possible on our iMacs?

Thanks in advance
 
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Here my experience with Big Sur/Monterey and Airport on an iMac 12.2 with AMD WX4150:
Could only play sound via AirPlay using the Music App. And only if an Airplay 1 device was in the connected mix the iMac also connected to Airplay 2 devices like a Marantz amplifier, latest firmware updated airport express, Sonos speaker, AppleTV 4. No video streaming via Airplay was possible.
For those who do not have have an Apple Airplay 1 device like Apple TV2 or a (not firmware updated) airport express, you can also use a Kodi box running Libreelec (in my case an Intel Nuc) as Airplay 1 device.
So I decided back to go back to Catalina+OCLP. The machine runs flawless now with full AirPlay 1 and 2 Audio/Video capabilities. SIP and SMB enabled.
Cheers
Just to add some successful experiments with AirPlay to Mac:

iMac12,2, M5100, Monterey 12.1 sending -> iMac12,2, WX4170 running Monterey 12.01 receiving
iMac12,2, WX4170 running Monterey 12.01 sending -> iMac11,3, RX480 running Monterey 12.1 receiving
iMac12,2, M5100, High Sierra sending -> iMac12,2, WX4170 running Monterey 12.01 receiving

Normal Airplay:
iMac12,2, M5100, High Sierra sending -> Apple 4K TV receiving
 
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Just to add some successful experiments with AirPlay to Mac:

iMac12,2, M5100, Monterey 12.1 sending -> iMac12,2, WX4179 running Monterey 12.01 receiving
iMac12,2, WX4179 running Monterey 12.01 sending -> iMac11,3, RX480 running Monterey 12.1 receiving
iMac12,2, M5100, High Sierra sending -> iMac12,2, WX4179 running Monterey 12.01 receiving

Normal Airplay:
iMac12,2, M5100, High Sierra sending -> Apple 4K TV receiving
Is it necessary to upgrade the Wifi card or patch the Atheros one for Airplay to work? Can I use AirPlay with only ethernet on my iMac?
 
Just to add some successful experiments with AirPlay to Mac:

iMac12,2, M5100, Monterey 12.1 sending -> iMac12,2, WX4179 running Monterey 12.01 receiving
iMac12,2, WX4179 running Monterey 12.01 sending -> iMac11,3, RX480 running Monterey 12.1 receiving
iMac12,2, M5100, High Sierra sending -> iMac12,2, WX4179 running Monterey 12.01 receiving

Normal Airplay:
iMac12,2, M5100, High Sierra sending -> Apple 4K TV receiving
Have you had success with iMac12,2 WX7100 (or any AMD Polaris/Ellesmere GPU) on Monterey 12.1 when sending -> Apple 4K TV receiving?

I took note of your prior post regarding a terminal command:
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-30699282

You specifically said it was for, "To enable AirPlay to Mac", and my goal is the reverse. For I still see the Apple TV as a selectable choice, but once picked the TV screen goes black and never shows anything, then goes back to the normal Apple TV screen once un-selected.

I'm still booting OCLP v0.3.1. The changelogs for v0.3.2-3 did not mention a fix for "from", only:
  • Fix AirPlay to Mac on macOS 12.1
Also, is the prior terminal command only needed if running OCLP older than v0.3.2?
 
Have you had success with iMac12,2 WX7100 (or any AMD Polaris/Ellesmere GPU) on Monterey 12.1 when sending -> Apple 4K TV receiving?

I took note of your prior post regarding a terminal command:
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-30699282

You specifically said it was for, "To enable AirPlay to Mac", and my goal is the reverse. For I still see the Apple TV as a selectable choice, but once picked the TV screen goes black and never shows anything, then goes back to the normal Apple TV screen once un-selected.

I'm still booting OCLP v0.3.1. The changelogs for v0.3.2-3 did not mention a fix for "from", only:
  • Fix AirPlay to Mac on macOS 12.1
Also, is the prior terminal command only needed if running OCLP older than v0.3.2?

Still no news about AirPlay to AppleTV 4K when using an AMD card and a macOS version later than Catalina. Unfortunately the community is not really working on this.

AirPlay works without any limits on iMac12,x NVIDIA systems with iGPU (@dosdude1 patched installation) or on all AMD iMac11,x and iMac12,x systems (GCN and Polaris/Ellesmere) up to Catalina (OCLP, no iGPU support needed).

It is really annoying to see AirPlay working on Monterey when trying Airplay to another Mac while getting the black screen on the AppleTV.

There must be a solution because the iMacPro1,1 uses a Xeon CPU (no iGPU) and the complete functionality is somehow managed by the (Vega) GPU.
 
iMac 11.3 (27" Mid 2010) AMD Radeon Pro WX4130 Boot Screen Mod Success!
Video of it working: https://drive.google.com/file/d/1VoLLea8-wOhLfukJ-M-kex3OuyQ-sSHy/view?usp=sharing

In a nutshell, Nick D's EG2 VBIOS, corresponding iMac firmware mod, and iMac backlight wiring mod. Bootscreen is working without an external monitor connected at all. (By the way, am I the first one to have done this successfully so far? surely someone's done it in the two years since it was first discovered - but it doesn't seem to be much talked about?)
Thanks so much @Ausdauersportler , @Nick [D]vB, and @internetzel for all their amazing work that made this possible!

What I did:
(Other stuff needed, aside from iMac and new GPU: access to another computer with Linux or macOS (or a linux live boot disk), CH341A or similar EEPROM programmer, soldering iron, 1.5 or so foot long piece of 3 conductor wire (I used a piece of telephone cable, and removed one of its 4 wires), optionally a PCI Express 6-pin power header extension, and a toggle switch (SPDT or DPDT (single/double pole, double throw) ON-ON or ON-OFF-ON type)).

Step 0: Have a way to boot Windows on the iMac (either on the internal drive, or in my case, plug in a hard drive from another computer - in my case, the drive with Windows 11 (EFI mode booting) from my Mac laptop (a 2009 year model MacBook Pro). Windows needs to be either the only boot option present, or set as the default, since you won't have access to ANY kind of boot picker right after swapping cards (not even OpenCore). At least that was the case for me.
Theoretically, any version of Windows that has drivers for the Polaris family GPUs (or maybe even anything that supports AMDVBFlashWin 2.93) should work - but when I tried booting a Legacy BIOS mode Windows 8.0 installation, all I got was a blank screen.....

Step 1: Swap the actual graphics cards. The usual procedure, just like the famous Post #1 of this thread. My 27" machine happened to have the smaller MXM Type A heatsink instead of the bigger Type B standard on 27" machines, due to having shipped with a Radeon HD 4670 originally. I think the Type B WX4130 fits in the full size MXM Type B heatsinks as well.
1.1: I'm not sure if the temperature sensor mod, of sticking the DVD drive temp sensor to the GPU heatsink in order for the system fan speeds to increase with GPU temp as they do with a stock Apple GPU, is necessary for the AMD Polaris GPUs - but I did it anyways.

Step 2: Boot the iMac up into Windows, and flash the EG2 VBIOS to the GPU. You can find the right VBIOS in this post: https://forums.macrumors.com/thread....1596614/page-414?post=29073783#post-29073783 . I used AMDVBFlashWin to do the flashing. You specifically need version 2.93 of this tool (attached to this post). The RX560 VBIOS from that post works on the WX4130, just as the post says.
side note: my WX4130 card, which came from a Dell Precision 7510 laptop, was a 2GB VRAM variant - but AMDVBFlashWin showed the the existing vBIOS on the card to be a 4GB one. I flashed the RX560 2GB variant VBIOS from the above post anyways, and it seems to work well.
And of course, be sure to make a backup of your original VBIOS, yaddi yaddi yaa.
plenty of tutorials for this already exist so I won't elaborate the procedure.

Step 3.1.1: software prep: (There might be a way to access the contents of the iMac's EFI BIOS firmware chip from the iMac itself, but I don't know it). So, I used a CH341A model EEPROM programmer tool, and a software called flashrom in Linux (linux mint in my case, but anything will do) on my Dell laptop. Easiest way to install flashrom on linux is a terminal command: sudo apt-get update; sudo apt-get install flashrom You can also use a computer with macOS for this software (install with homebrew). If using linux, you don't need the operating system installed, just boot from an installer disk and use Live mode (Tryout mode, or whatever it's called).

Step 3.1.2 Connect the iMac's firmware chip to your EEPROM programmer tool. An SOIC clip won't work (in my case at least), you need to desolder the chip from the iMac's mainboard in order to disable a write-protection that Apple has wired to it, so desolder it from the iMac - being extremely careful not to break any of the fine electrical traces on the mainboard that connect to the chip (I used plenty of solder flux paste, a wide soldering tip that touches all 4 pins of each side of the chip at once, a very thin screwdriver to pry the chip up once the solder joints melt, and the soldering heat set to 375 degrees to remove the chip one side at a time. Patience is Key here - if you try to pry the chip off before the solder joints melt, you will break the fine electrical connections - as I have had happen on other computers.) Also note down the orientation of the chip - there's a tiny dip in one corner of the chip signifying the position of pin #1, and the chip needs to go back on in the same orientation. Once it's removed, you can either just solder eight tiny wires to connect the chip to your programmer (tedious) or buy and use a socket that plugs into the programmer and lets you simply keep and clamp the chip on. (I have no idea what those are called)

Step 3.2: Next, read the contents of the iMac's firmware chip into a binary dump file. On linux, the easiest way to do this is a terminal command (once you plug the programmer tool into the computer's USB port) : flashrom -p ch341a_spi -r imac_orig.bin . This will save the chip contents to a BIN file in the user's home folder. Make sure the file is there, then unplug the programmer tool from the USB port. Duplicate this file, so that you have a spare copy of the original firmware. If you're working from a Live Boot-ed Linux thing, save the copy to a USB drive or something where it'll be safe.

Step 3.3: Use a software called UEFITool to add two "modules" to the iMac's firmware. Download link: https://github.com/LongSoft/UEFITool/releases/tag/0.26.0 (beware: you need specfically UEFITool version 0.26, which is what is used in the video, NOT the latest A59 or whatever is available on GitHub. The new one looks quite different (it will throw off someone who hasn't done such work before and is just following the video, like me) and in my case just errored out when I tried to do things). Again, the files you need are in the above linked post (you need the FFS.zip file). Procedure: Just follow the video linked in that post to a tee. You might not know what each line of seemingly gibberish is, but neither did I - just matching the lines of gibberish on my screen to the lines of gibberish in the video worked for me. "Data dump system administration". Save the modified file with a new name (imac_modded.bin for example).

Step 3.4: Write the modified firmware to the iMac's firmware chip. Plug the EEPROM chip programmer tool back into a USB port, and run a terminal command: flashrom -p ch341a_spi -w imac_modded.bin (or whatever you called your modified firmware file. Solder the chip back to the iMac's mainboard, of course making sure it's in exactly the right position and orientation.

Step 3.5 Reassemble the iMac, pray to whatever higher being(s) you believe in, and push the power button :) If all is well, you'll hear the startup chime (unless you had audio muted) meaning the machine is alive. If you have a DisplayPort connected monitor, plug it in and make sure you see the bootscreen on it (at this stage, internal bootscreen won't work. Windows stays on the external monitor, and macOS only turns on the internal screen once it finishes 70-ish percent of its bootup process)

Step 4 Now for the hardware hackery :)

The idea for this comes from this post:
https://forums.macrumors.com/thread...e.1596614/page-90?post=27485731#post-27485731
Read that post for more on the mod. All credit for the idea goes to the author of that post, Nick D.

Objective: In order to get the bootscreen to show on the iMac's internal display, the internal display's backlight needs to be manually forced on, as the firmware on the graphics card isn't doing it automatically. The iMac uses a pulse modulated 3.3V signal to the display backlight power supply board to determine screen brightness - so if that line gets no power, the brightness will be 0 - ie off. And if it gets a steady 3.3 volts, it will be 100% - full brightness. At boot up time, this line is probably getting zero volts, so the screen stays off. The workaround is to manually feed it 3.3 volts at bootup time to force the display on. But if you permanently wire a 3.3v supply into it, your screen will always be stuck at 100% brightness, with no way to adjust it. So what needs to be done is have it get 3.3V full input at bootup, and change it to get the standard, modulated, adjustable signal from the iMac's mainboard after the computer boots up. So I added a toggle switch, where you can flip it to the 3.3V steady line while booting, and flip it to the standard connection afterwards.

Step 4.0.1 remove your iMac display of course

Step 4.1 In your PCI-Express power extension cable, cut the wire from the lower left pin (if looking from the wires side of the connector) of the plug end of the extension. Cut the cable about 6 inches away from the plug. See the attached pictures - make sure you cut the right wire. Strip both cut ends, and solder a 1.5 foot or so long wire to each cut end. Insulate the solder joints. This is where the telephone cable from earlier is useful, since it has 3 wires bundled together (it has 4, but you can pull out one to be left with 3)

Step 4.2 Find a double throw, on-on or on-off-on toggle switch. On-on because in both positions, the switch needs to connect something. In one position, it connects to a 3.3V supply that I tapped from the iMac's PSU, and in the other position, it connects back to the wire that it originally went to. If you use an on-off-on switch, which has 3 positions (a middle position where the wire connects to nothing), you can have a position of the switch where the internal display can be turned off altogether while the computer is running - which for me is excellent because I can leave the computer processing something without wasting power for the display on a task that doesn't need me to keep looking at the screen. I really wish Apple had done that to begin with..... Obviously, this is the type of switch I used.

Step 4.3 Solder: 1) the (extended) cut wire coming from the plug end of the PCIe power extension cable (ie the backlight power board end) to the middle pin of the double throw switch, 2) The other (extended) cut wire, the one from the socket end of the PCIe power extension, ie the mainboard end of the cable, to one of the sides of the switch (again, see the pictures for details).

Step 4.4: Solder another wire connecting a 3.3 volt supply pin from the iMac's power supply (see attached pictures for which one this is) to the other side pin of the toggle switch.

Step 4.5 Remove the iMac's LCD backlight power supply board, unplug the 6 pin cable that goes into it, and plug in the extension cable you just modified. Then plug the cable that used to plug into the backlight power board into the socket end of the modified extension cable. Tuck the cables so that they won't block the screen from sitting flush.

Step 4.6 (optional) you can drill a hole in the iMac's shell somewhere to mount the switch. This is easiest if you used a switch with a round post - so just drill a round hole and mount it through that. I made the hole in the bottom speaker grill, just to the left of the RAM card bay where there is a spot clear from the inside. Looks really neat IMO :)

Step 4.7 route the cables neatly and reassemble your iMac

---------------

Now you can move the switch to one side while booting the machine up for bootscreen, then once it boots up switch it to the other side for normal brightness control!
Note: If you do still keep an external monitor connected, the iMac still shows the bootscreen only on that, and ignores the internal display even if you have the switch set to enable it. You have to disconnect the external display for the internal bootscreen to work.

The AMD Radeon Polaris family cards are excellent - you get (with OpenCore) seamless operation and updating with the latest macOS versions, and great performance. My machine runs macOS 12.2 beta brilliantly (I've upgraded everything that can be upgraded - CPU to a quad core 2.93GHz Intel Xeon X3470, WLAN card to the Broadcom BCM943602CDP, and added a solid state drive for the OS to boot from (piggybacked it with a 3.5" drive for data storage, so as to use a relatively cheap small solid state drive) and 16GB RAM. And to think Apple dropped support for this model with macOS 10.13.......
My Radeon WX4130 card cost me $70 on eBay. According to the seller, it came from a Dell Precision 7510 laptop. I couldn't find any WX4150 or WX4170 cards for sale, and the WX7100 was stupid expensive at 300 and some dollars :-(

With this, I'd now recommend anyone upgrading the graphics card in their Apple iMac to go with a Radeon instead of the nVidia Kepler family of cards that's been the easiest solution until now - since the Kepler ones now need update-breaking driver patches to run macOS 12. Until now they held the title of being the only ones to show the boot menu properly... They reign no longer! (Yeah, this is a notable amount more work, and higher chance of killing the iMac altogether, but no functionality lost!)

Wow I just typed a lot..... hopefully someone finds it useful. Bye 20211229_125305.jpg20211211_204515.jpg20211211_205020.jpg20211211_204442#1.jpg20211229_190544.jpg20211229_190552.jpg20211229_190737.jpg20211229_192318.jpg20211229_192322.jpg20211229_202356.jpg
 
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Just thought moving over to this thread would minimize the risk of getting punished for posting more off-topic posts.

Basically I used the USB3 drivers test as a proof of concept to achieve the same thing @internetzel asked for last summer. During vBIOS development the most time will be wasted into the recovery from bad flashes. Our main goal is getting the EFI Boot picker working on AMD cards and each time I do another test the risk of getting a brick is not zero.

So your Driver#### method is the only solution acting early enough to test new vBIOS versions. Unfortunately I got no single successful load during the last days. Before trying the USB3 stack I was using vBIOS drivers.

Do you have a simple must load efi driver to check if this method is still possible on our iMacs?
Well I know apfs.efi works from Driver#### because I can see Catalina and Big Sur and Monterey preboot volumes in the Apple Startup Manager of my MacPro3,1 (of course only the dosdude Catalina will work from the Apple Startup Manager on my MacPro3,1)
If your firmware has apfs built-in, then I suppose you could try a different file system driver such as ntfs, btrfs, ext4.
I'm not sure - does FixPCIeLinkRate.efi work from Driver####? I want to separate the link rate fix functionality (make it a driver) from the pcitree output (make it an app).

I've attached some EFI stuff. I haven't tried some of them. I think I had issues including ntfs or nvme with apfs?
I think ReloadPCIRom.efi doesn't do anything special so that might be one to try to test if Driver#### will load it.
If XhciDxe.efi from MacPro6,1 requires UEFI 2.0 stuff, then maybe FakeUEFI2.efi will make it work.
The XhciDxe.efi that I made doesn't require UEFI 2.0 but it has a bunch of debug messages and is a work in progress. Maybe it would work with the other two drivers from MacPro6,1?
I think CrScreenshotDxe.efi requires GOP driver. I want to make something that will work with UGA so I can take a screenshot of the Apple Startup Manager on my MacPro3,1 (it should have an nvram variable to allow changing the key used for taking the screenshot). Maybe a UGAonGOP driver would be useful here. OpenCore has some code for that. I've included a GOPonUGA driver but haven't tried it - I think it's safe.
FvSimpleFileSystem.efi and Fv2OnFvThunk.efi should be harmless. They create a file system from firmware volumes so you can list, load, and run efi apps and drivers from the firmware in the EFI Shell. Load Fv2OnFvThunk.efi first to make an old firmware volume look like a new one so the FvSimpleFileSystem driver will work with it.

Check RefindPlus debug log to see what version of EFI you have. If it's EFI 1.1 then hopefully that's the reason the vBIOS drivers won't load?
Capture a dmpstore from the EFI Shell. output to see if any nvram variables might relate to the Driver#### issue if you can't get anything to work.
 

Attachments

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iMac 11.3 (27" Mid 2010) AMD Radeon Pro WX4130 Boot Screen Mod Success!
Video of it working: https://drive.google.com/file/d/1VoLLea8-wOhLfukJ-M-kex3OuyQ-sSHy/view?usp=sharing

In a nutshell, Nick D's EG2 VBIOS, corresponding iMac firmware mod, and iMac backlight wiring mod. Bootscreen is working without an external monitor connected at all. (By the way, am I the first one to have done this successfully so far? surely someone's done it in the two years since it was first discovered - but it doesn't seem to be much talked about?)
Thanks so much @Ausdauersportler , @Nick [D]vB, and @internetzel for all their amazing work that made this possible!

What I did:
(Other stuff needed, aside from iMac and new GPU: access to another computer with Linux or macOS (or a linux live boot disk), CH341A or similar EEPROM programmer, soldering iron, 1.5 or so foot long piece of 3 conductor wire (I used a piece of telephone cable, and removed one of its 4 wires), optionally a PCI Express 6-pin power header extension, and a toggle switch (SPDT or DPDT (single/double pole, double throw) ON-ON or ON-OFF-ON type)).

Step 0: Have a way to boot Windows on the iMac (either on the internal drive, or in my case, plug in a hard drive from another computer - in my case, the drive with Windows 11 (EFI mode booting) from my Mac laptop (a 2009 year model MacBook Pro). Windows needs to be either the only boot option present, or set as the default, since you won't have access to ANY kind of boot picker right after swapping cards (not even OpenCore). At least that was the case for me.
Theoretically, any version of Windows that has drivers for the Polaris family GPUs (or maybe even anything that supports AMDVBFlashWin 2.93) should work - but when I tried booting a Legacy BIOS mode Windows 8.0 installation, all I got was a blank screen.....

Step 1: Swap the actual graphics cards. The usual procedure, just like the famous Post #1 of this thread. My 27" machine happened to have the smaller MXM Type A heatsink instead of the bigger Type B standard on 27" machines, due to having shipped with a Radeon HD 4670 originally. I think the Type B WX4130 fits in the full size MXM Type B heatsinks as well.
1.1: I'm not sure if the temperature sensor mod, of sticking the DVD drive temp sensor to the GPU heatsink in order for the system fan speeds to increase with GPU temp as they do with a stock Apple GPU, is necessary for the AMD Polaris GPUs - but I did it anyways.

Step 2: Boot the iMac up into Windows, and flash the EG2 VBIOS to the GPU. You can find the right VBIOS in this post: https://forums.macrumors.com/thread....1596614/page-414?post=29073783#post-29073783 . I used AMDVBFlashWin to do the flashing. You specifically need version 2.93 of this tool (attached to this post). The RX560 VBIOS from that post works on the WX4130, just as the post says.
side note: my WX4130 card, which came from a Dell Precision 7510 laptop, was a 2GB VRAM variant - but AMDVBFlashWin showed the the existing vBIOS on the card to be a 4GB one. I flashed the RX560 2GB variant VBIOS from the above post anyways, and it seems to work well.
And of course, be sure to make a backup of your original VBIOS, yaddi yaddi yaa.
plenty of tutorials for this already exist so I won't elaborate the procedure.

Step 3.1.1: software prep: (There might be a way to access the contents of the iMac's EFI BIOS firmware chip from the iMac itself, but I don't know it). So, I used a CH341A model EEPROM programmer tool, and a software called flashrom in Linux (linux mint in my case, but anything will do) on my Dell laptop. Easiest way to install flashrom on linux is a terminal command: sudo apt-get update; sudo apt-get install flashrom You can also use a computer with macOS for this software (install with homebrew). If using linux, you don't need the operating system installed, just boot from an installer disk and use Live mode (Tryout mode, or whatever it's called).

Step 3.1.2 Connect the iMac's firmware chip to your EEPROM programmer tool. An SOIC clip won't work (in my case at least), you need to desolder the chip from the iMac's mainboard in order to disable a write-protection that Apple has wired to it, so desolder it from the iMac - being extremely careful not to break any of the fine electrical traces on the mainboard that connect to the chip (I used plenty of solder flux paste, a wide soldering tip that touches all 4 pins of each side of the chip at once, a very thin screwdriver to pry the chip up once the solder joints melt, and the soldering heat set to 375 degrees to remove the chip one side at a time. Patience is Key here - if you try to pry the chip off before the solder joints melt, you will break the fine electrical connections - as I have had happen on other computers.) Also note down the orientation of the chip - there's a tiny dip in one corner of the chip signifying the position of pin #1, and the chip needs to go back on in the same orientation. Once it's removed, you can either just solder eight tiny wires to connect the chip to your programmer (tedious) or buy and use a socket that plugs into the programmer and lets you simply keep and clamp the chip on. (I have no idea what those are called)

Step 3.2: Next, read the contents of the iMac's firmware chip into a binary dump file. On linux, the easiest way to do this is a terminal command (once you plug the programmer tool into the computer's USB port) : flashrom -p ch341a_spi -r imac_orig.bin . This will save the chip contents to a BIN file in the user's home folder. Make sure the file is there, then unplug the programmer tool from the USB port. Duplicate this file, so that you have a spare copy of the original firmware. If you're working from a Live Boot-ed Linux thing, save the copy to a USB drive or something where it'll be safe.

Step 3.3: Use a software called UEFITool to add two "modules" to the iMac's firmware. Download link: https://github.com/LongSoft/UEFITool/releases/tag/0.26.0 (beware: you need specfically UEFITool version 0.26, which is what is used in the video, NOT the latest A59 or whatever is available on GitHub. The new one looks quite different (it will throw off someone who hasn't done such work before and is just following the video, like me) and in my case just errored out when I tried to do things). Again, the files you need are in the above linked post (you need the FFS.zip file). Procedure: Just follow the video linked in that post to a tee. You might not know what each line of seemingly gibberish is, but neither did I - just matching the lines of gibberish on my screen to the lines of gibberish in the video worked for me. "Data dump system administration". Save the modified file with a new name (imac_modded.bin for example).

Step 3.4: Write the modified firmware to the iMac's firmware chip. Plug the EEPROM chip programmer tool back into a USB port, and run a terminal command: flashrom -p ch341a_spi -w imac_modded.bin (or whatever you called your modified firmware file. Solder the chip back to the iMac's mainboard, of course making sure it's in exactly the right position and orientation.

Step 3.5 Reassemble the iMac, pray to whatever higher being(s) you believe in, and push the power button :) If all is well, you'll hear the startup chime (unless you had audio muted) meaning the machine is alive. If you have a DisplayPort connected monitor, plug it in and make sure you see the bootscreen on it (at this stage, internal bootscreen won't work. Windows stays on the external monitor, and macOS only turns on the internal screen once it finishes 70-ish percent of its bootup process)

Step 4 Now for the hardware hackery :)

The idea for this comes from this post:
https://forums.macrumors.com/thread...e.1596614/page-90?post=27485731#post-27485731
Read that post for more on the mod. All credit for the idea goes to the author of that post, Nick D.

Objective: In order to get the bootscreen to show on the iMac's internal display, the internal display's backlight needs to be manually forced on, as the firmware on the graphics card isn't doing it automatically. The iMac uses a pulse modulated 3.3V signal to the display backlight power supply board to determine screen brightness - so if that line gets no power, the brightness will be 0 - ie off. And if it gets a steady 3.3 volts, it will be 100% - full brightness. At boot up time, this line is probably getting zero volts, so the screen stays off. The workaround is to manually feed it 3.3 volts at bootup time to force the display on. But if you permanently wire a 3.3v supply into it, your screen will always be stuck at 100% brightness, with no way to adjust it. So what needs to be done is have it get 3.3V full input at bootup, and change it to get the standard, modulated, adjustable signal from the iMac's mainboard after the computer boots up. So I added a toggle switch, where you can flip it to the 3.3V steady line while booting, and flip it to the standard connection afterwards.

Step 4.0.1 remove your iMac display of course

Step 4.1 In your PCI-Express power extension cable, cut the wire from the lower left pin (if looking from the wires side of the connector) of the plug end of the extension. Cut the cable about 6 inches away from the plug. See the attached pictures - make sure you cut the right wire. Strip both cut ends, and solder a 1.5 foot or so long wire to each cut end. Insulate the solder joints. This is where the telephone cable from earlier is useful, since it has 3 wires bundled together (it has 4, but you can pull out one to be left with 3)

Step 4.2 Find a double throw, on-on or on-off-on toggle switch. On-on because in both positions, the switch needs to connect something. In one position, it connects to a 3.3V supply that I tapped from the iMac's PSU, and in the other position, it connects back to the wire that it originally went to. If you use an on-off-on switch, which has 3 positions (a middle position where the wire connects to nothing), you can have a position of the switch where the internal display can be turned off altogether while the computer is running - which for me is excellent because I can leave the computer processing something without wasting power for the display on a task that doesn't need me to keep looking at the screen. I really wish Apple had done that to begin with..... Obviously, this is the type of switch I used.

Step 4.3 Solder: 1) the (extended) cut wire coming from the plug end of the PCIe power extension cable (ie the backlight power board end) to the middle pin of the double throw switch, 2) The other (extended) cut wire, the one from the socket end of the PCIe power extension, ie the mainboard end of the cable, to one of the sides of the switch (again, see the pictures for details).

Step 4.4: Solder another wire connecting a 3.3 volt supply pin from the iMac's power supply (see attached pictures for which one this is) to the other side pin of the toggle switch.

Step 4.5 Remove the iMac's LCD backlight power supply board, unplug the 6 pin cable that goes into it, and plug in the extension cable you just modified. Then plug the cable that used to plug into the backlight power board into the socket end of the modified extension cable. Tuck the cables so that they won't block the screen from sitting flush.

Step 4.6 (optional) you can drill a hole in the iMac's shell somewhere to mount the switch. This is easiest if you used a switch with a round post - so just drill a round hole and mount it through that. I made the hole in the bottom speaker grill, just to the left of the RAM card bay where there is a spot clear from the inside. Looks really neat IMO :)

Step 4.7 route the cables neatly and reassemble your iMac

---------------

Now you can move the switch to one side while booting the machine up for bootscreen, then once it boots up switch it to the other side for normal brightness control!
Note: If you do still keep an external monitor connected, the iMac still shows the bootscreen only on that, and ignores the internal display even if you have the switch set to enable it. You have to disconnect the external display for the internal bootscreen to work.

The AMD Radeon Polaris family cards are excellent - you get (with OpenCore) seamless operation and updating with the latest macOS versions, and great performance. My machine runs macOS 12.2 beta brilliantly (I've upgraded everything that can be upgraded - CPU to a quad core 2.93GHz Intel Xeon X3470, WLAN card to the Broadcom BCM943602CDP, and added a solid state drive for the OS to boot from (piggybacked it with a 3.5" drive for data storage, so as to use a relatively cheap small solid state drive) and 16GB RAM. And to think Apple dropped support for this model with macOS 10.13.......
My Radeon WX4130 card cost me $70 on eBay. According to the seller, it came from a Dell Precision 7510 laptop. I couldn't find any WX4150 or WX4170 cards for sale, and the WX7100 was stupid expensive at 300 and some dollars :-(

With this, I'd now recommend anyone upgrading the graphics card in their Apple iMac to go with a Radeon instead of the nVidia Kepler family of cards that's been the easiest solution until now - since the Kepler ones now need update-breaking driver patches to run macOS 12. Until now they held the title of being the only ones to show the boot menu properly... They reign no longer! (Yeah, this is a notable amount more work, and higher chance of killing the iMac altogether, but no functionality lost!)

Wow I just typed a lot..... hopefully someone finds it useful. ByeView attachment 1936163View attachment 1936164View attachment 1936165View attachment 1936166View attachment 1936167View attachment 1936168View attachment 1936169View attachment 1936170View attachment 1936171View attachment 1936174
Great work!
I've got to add that it's no longer necessary to do the bootrom firmware mod, if you can live without graphics acceleration in Windows. I found a (yet unpublished) way to add those two EFI modules to the VBIOS itself.
In case there's actual interest in such VBIOSes for the Polaris GPUs (Baffin and Ellesmere) I can publish them.
 
Somehow I managed to get Netflix playing in Safari.
My setup is iMac11,1, upgraded with wx4130 per the instructions on page #1.
Apple TV app and Disney+, Amazon Prime on Safari all works as expected, only Netflix doesn't work.

Under Safari, I turned on developer mode menu, and I played around with changing the user agent to Firefox, Chrome, Microsoft Edge. None of them worked, Netflix refused to play anything.
I then installed Microsoft Edge for Mac, and played some Netflix using the Edge browser, it works.
Now I closed the Microsoft Edge browser and reopened the Safari browser. Now all of a sudden Netflix in Safari works !!!
I even removed the Microsoft edge app to the trash, Safari still work playing Netflix.

Only bad news is, Netflix in Safari is only playing in 960x540 resolution so far for me. Maybe somebody can help figure out how to play in 1080p or even 4K. (I'm only subscribed to the lowest tier of Netflix which limits resolution to 960x540)

Interesting observation: I tried to use the built in screen capture app to take a screen shot of the Netflix window, but the saved image is always blank, I had to use my cellphone to take a picture of my desktop to prove that Netflix is working on my iMac.
 

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Figured I'd just upload my original K4000M bios and pictures of the card in case anyone can develop on it.

Let me know if there's a better place to post.

Only issue I'm running into on the 12,2 is that it cannot wake from sleep, and after cutting the power, and powering the iMac on, maybe 33% of the time the usb devices arn't properly powered on.
 

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Somehow I managed to get Netflix playing in Safari.
My setup is iMac11,1, upgraded with wx4130 per the instructions on page #1.
Apple TV app and Disney+, Amazon Prime on Safari all works as expected, only Netflix doesn't work.

Under Safari, I turned on developer mode menu, and I played around with changing the user agent to Firefox, Chrome, Microsoft Edge. None of them worked, Netflix refused to play anything.
I then installed Microsoft Edge for Mac, and played some Netflix using the Edge browser, it works.
Now I closed the Microsoft Edge browser and reopened the Safari browser. Now all of a sudden Netflix in Safari works !!!
I even removed the Microsoft edge app to the trash, Safari still work playing Netflix.

Only bad news is, Netflix in Safari is only playing in 960x540 resolution so far for me. Maybe somebody can help figure out how to play in 1080p or even 4K. (I'm only subscribed to the lowest tier of Netflix which limits resolution to 960x540)

Interesting observation: I tried to use the built in screen capture app to take a screen shot of the Netflix window, but the saved image is always blank, I had to use my cellphone to take a picture of my desktop to prove that Netflix is working on my iMac.
Netflix works without any changes on iMac12,2 + WX4170 using Monterey 12.01 (a relative of your card). Video screen capturing is broken since Big Sur with this type of card (reason unknown, my RX480 works fine in my iMac11,3).

Taking normal still screen shots works perfectly. Even from my Safari playing Netflix ….
 
Netflix works without any changes on iMac12,2 + WX4170 using Monterey 12.01 (a relative of your card). Video screen capturing is broken since Big Sur with this type of card (reason unknown, my RX480 works fine in my iMac11,3).

Taking normal still screen shots works perfectly. Even from my Safari playing Netflix ….
I don't have Netflix account and thus can't comment on that.
However, video screen capture works flawless in my iMac 11,3 (27" 2010) with RX480 for YouTube videos or Zoom meetings in Big Sur & Monterey.
 
AMD card has no acceleration (wrong or missing OpenCore or OCLP installation, post #1)
After 'successfully' started the iMac 2011 21.5 & 27 with the WX4130. I installed OCLP and did the 'TUI' post install (did not tweak anything, just use the auto option). I experience a rather unstable system. I tried Monterey for a few days and now Big Sur, and both macOS on both 21.5 & 27 started crashing and/or slow down when using Chrome (and sometimes Safari) or Photos app. It basically kicks you out of the desktop environment and goes back to the user login screen (no reboot or anything). Often it mentions the following:

Termination Reason: Namespace SIGNAL, Code 11 Segmentation fault: 11
Terminating Process: exc handler [773]

Termination Reason: Namespace SIGNAL, Code 11 Segmentation fault: 11
Terminating Process: exc handler [146]

Termination Reason: Namespace SIGNAL, Code 4 Illegal instruction: 4
Terminating Process: exc handler [817]

I was hoping by using Big Sur it would have been different, but it still started to crash. For me this could be a GPU issue or a Monterey/BigSur/OCLP issue. I would appreciate if someone could give me a nudge in the right directions how can I approach this?
 
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After 'successfully' started the iMac 2011 21.5 & 27 with the WX4130. I installed OCLP and did the 'TUI' post install (did not tweak anything, just use the auto option). I experience a rather unstable system. I tried Monterey for a few days and now Big Sur, and both macOS on both 21.5 & 27 started crashing and/or slow down when using Chrome (and sometimes Safari) or Photos app. It basically kicks you out of the desktop environment and goes back to the user login screen (no reboot or anything). Often it mentions the following:



I was hoping by using Big Sur it would have been different, but it still started to crash. For me this could be a GPU issue or a Monterey/BigSur/OCLP issue. I would appreciate if someone could give me a nudge in the right directions how can I approach this?
I had initially similar issues with my iMac 21.5 from 2011 and Nvidia quadro k2100m with Monterey and BigSur. Finally I found out that I had conflicting OLCP folders in 2 different EFI. On Boot the wrong patch was loaded although I patched the system into the “right” partition. There might be other reasons…but check if you have a single EFI with OCLP and system is loading this one.
 
I had initially similar issues with my iMac 21.5 from 2011 and Nvidia quadro k2100m with Monterey and BigSur. Finally I found out that I had conflicting OLCP folders in 2 different EFI. On Boot the wrong patch was loaded although I patched the system into the “right” partition. There might be other reasons…but check if you have a single EFI with OCLP and system is loading this one.
Ha! That worked. I indeed added an extra boot drive as a spare / backup. When I removed it (I formatted it clean) then all the “problems” disappears (well I un/re patched OCLP). Now I understand why people said it “all works”… many many thanks! Was really pulling my hair out. Didn’t really wanted to redo the whole GPU thing….
 
I’m deep into my project. Stripped the iMac apart last night. I’m going for the baking procedure to start with and see if it buys time at no expense for now. I'm evaluating the options for a replacement card like on another iMac done about a year ago, but by a hired tech.

I’m wondering if the piece of plastic in the photo is very necessary. It seems that if it partitions things with little walls between drive bays it might inhibit airflow. Has anyone just left it out? The only thing I can see it offers is support to the back of the logic board. It seems to be a possible pinch hazard for wires.

I’m planning on going with just one SSD instead of the SSD (OWC data doubler in optical slot) and the 3TB HDD I had in there while using it as a recording studio machine. I reckon that with the unit being taken from star performer status I could at least try a few things to minimize the heat issues, and open space seems like it could help—no second drive, less hardware inside, more space.

What say the wizards?
 

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Great work!
I've got to add that it's no longer necessary to do the bootrom firmware mod, if you can live without graphics acceleration in Windows. I found a (yet unpublished) way to add those two EFI modules to the VBIOS itself.
In case there's actual interest in such VBIOSes for the Polaris GPUs (Baffin and Ellesmere) I can publish them.
Yeah, I remember you mentioning this to me in the PM. I do think it would help a lot of people if you published the VBIOS that doesn't need iMac firmware modding - as that's probably the step where serious hardware and/or software/firmware damage (bricking) is most likely to happen. As for Windows, I think you mentioned that EFI mode Windows works fine? if so, it's probably fine to lose the VGA module.

Or maybe is it possible to make a version of the VBIOS that has the VGA module and the EG stuff, and let it increase in size? So that people who want to use it can replace the VBIOS EEPROM chip on their GPU card with a larger capacity one that can accommodate it. Similar to what needs to be done to boot-screen flash desktop RX580 cards for Mac Pro computers.

I had already completed the iMac firmware mod by the time I heard of the new vBIOS from you, which is why I went ahead with this anyways. And I believe the new one also needs a monitor to be hooked up, for the internal bootscreen to work?
Also I really like the display killswitch lol
 
Yeah, I remember you mentioning this to me in the PM. I do think it would help a lot of people if you published the VBIOS that doesn't need iMac firmware modding - as that's probably the step where serious hardware and/or software/firmware damage (bricking) is most likely to happen. As for Windows, I think you mentioned that EFI mode Windows works fine? if so, it's probably fine to lose the VGA module.
While EFI booting in to Windows will work, you'd still have no graphics acceleration in Windows because the AMD driver don't like that stripped down VBIOS.
Or maybe is it possible to make a version of the VBIOS that has the VGA module and the EG stuff, and let it increase in size? So that people who want to use it can replace the VBIOS EEPROM chip on their GPU card with a larger capacity one that can accommodate it. Similar to what needs to be done to boot-screen flash desktop RX580 cards for Mac Pro computers.
Unfortunately with AMD cards only the first 128 kB of the VBIOS EEPROM can be used for EFI drivers - at least in our iMacs. No other way to gain the needed space than by removing the legacy BIOS graphics driver.
I had already completed the iMac firmware mod by the time I heard of the new vBIOS from you, which is why I went ahead with this anyways. And I believe the new one also needs a monitor to be hooked up, for the internal bootscreen to work?
Also I really like the display killswitch lol
That depends on the EFI graphics driver used in the VBIOS. When using the same EFI driver that you put into the bootrom firmware, you'd get the same behaviour that you currently have.
And when using the other EFI graphics driver, one of those small miniDP-Dongles that emulate a display would do the job.
 
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I did backup the original rom as attached, along with a photo.
Question: Which IC is the ROM, and if I can use a "TZT Original CH341A 24 25 Series EEPROM Flash BIOS USB Programmer Module + SOIC8 SOP8 Test Clip For EEPROM 93CXX / 25CXX / 24CXX" to program the ROM for my bricked W6170M card?

Happy New
Year to all 🍾🎆
 
Question: Which IC is the ROM, and if I can use a "TZT Original CH341A 24 25 Series EEPROM Flash BIOS USB Programmer Module + SOIC8 SOP8 Test Clip For EEPROM 93CXX / 25CXX / 24CXX" to program the ROM for my bricked W6170M card?

Happy New
Year to all 🍾🎆
Happy New Year!

There is only one such chip on the top side, left edge, in the middle and there is a small white arrow marking pin 1.
You cannot miss it. Using a clip can be a really frustrating experience, mostly one needs three hands, the third to enter the flashing command while the first two have to fix the clip.

Have fun!
 
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I’m deep into my project. Stripped the iMac apart last night. I’m going for the baking procedure to start with and see if it buys time at no expense for now.

I’m wondering if the piece of plastic in the photo is very necessary. It seems that if it partitions things with little walls between drive bays it might inhibit airflow. Has anyone just left it out? The only thing I can see it offers is support to the back of the logic board. It seems to be a possible pinch hazard for wires.

I’m planning on going with just one SSD instead of the SSD (OWC data doubler in optical slot) and the 3TB HDD I had in there while using it as a recording studio machine. I reckon that with the unit being taken from star performer status I could at least try a few things to minimize the heat issues, and open space seems like it could help—no second drive, less hardware inside, more space.

What say the wizards?
A little after posting that, I baked the card, padded & pasted, and put it all together with just one SSD inside, leaving out that piece of plastic and left the optical spot empty. On first instance of plugging in, I got the three LEDs. Nice. Then I put the screen on and booted up. Nice. Did SMC reset and NVRAM reset too.

Geekbench testing didn't serve me so well. Since I am just reinstalling the stock card, the OpenCL test was the only graphics test available. That didn't work out right. It took about 10 minutes, and at some point late in that window, the mouse and keyboard (full size USB keyboard with mouse attached) seized up. The machine went to the black glowing screen. I figured I'd do another SMC and NVRAM reset. Did. Came back to another Geekbench test. The first one coincided with my iCloud syncing kicking in and managing a bunch of desktop/doc stuff that fell out of sync with this one drive for a month. I don't think that alone made Geekbench choke it but that was not a thing on the second test. That second test also took 10 minutes and froze the mouse/keyboard, but I let it go. It went to the glowing black screen again and I let that go. Then it came back to the login screen, dimmed about half. While it didn't respond to keyboard or mouse right away, it did relent after 3.5 minutes and I logged in and screwed around for maybe 20 minutes, checking apps, using Photoshop to do repeated filters and blurs and other bits. Checked some 4k YouTube. Opened apps and did Quick Look on different files. Things were doing okay without the Geekbench. Tried sleep. Came back okay.

Holidays beckoned so I had to go away for the night. I'll get back to it and see how it handles more sustained use and find suitable fan settings, but the basic renewal worked and at least my effort was rewarded with that much. I'm still evaluating the replacement card options. At least going through the exercise made the process familiar so taking it apart again won't be so daunting.

Thanks to Vinay P for some DM support along the way.
 
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My Mac I plan to upgrade:
iMac 11,1 (2009 Late) 27-inch, i7 CPU, 16GB memory.
The original Radeon HD 4850/512MB failed years ago, and was replaced with another iMac's Radeon HD 4670/256MB.
The optical drive has been replaced with an optibay enclosure and a 120GB SSD (High Sierra boots from this), the thermal sensor is stuck on this SSD. The original HDD is still in place, but not used for booting, only for data storage.

This is what I have prepared for the upgrade:
A.) Expected latest iMac 11,1 firmware version on High Sierra = 63.0.0.0.0
https://eclecticlight.co/2018/10/31/which-efi-firmware-should-your-mac-be-using-version-3/
B.) nVIDIA card: GPU reads N15P-Q1-A2, RAMs read SKhynix.
This should be a K1100M. And the appropriate ROM for this appears to be as shown next.
C.) Nick[D]vB's Quadro_Beta1.2/K1100.rom with an md5 of 30a855b2253eaf8c1cd94b2a6bfb5b16 from this post:
https://forums.macrumors.com/thread....1596614/page-152?post=28046843#post-28046843
D.) New 1TB SATA SSD
E.) OWC/MacSales HDD thermal adapter cable.
F.) DIY plastic adapter to hold the 2.5" SSD in place of the original 3.5" HDD.
G.) The_Croupier's Linux USB image from this post:
https://forums.macrumors.com/thread....1596614/page-545?post=29723850#post-29723850
USB drive formatted for GPT, FAT32. Mac_GPU_Flash.zip contents extracted to the FAT32 volume.
ROM file C.) placed on FAT32 volume under /flash/QUADRO/K1100.rom, all other .rom files removed.
H.) SHOULD, but NOT YET HAVE: Installer USB of macOS Catalina or later.

This is my action plan:
1.) Download latest High Sierra installer, do a new full install, download and install all available updates, confirm firmware is the latest (repeat all this otherwise).
2.) While on a working system, note down the wired Ethernet MAC address of the iMac, so that later when it starts without a functioning screen, I will still know what IP address it listens on.
3.) Test-boot the Linux USB drive (G.), make sure it loads, and I can connect via ssh. Then power off.
4.) Disassemble the iMac, remove the current Radeon HD card, replace it with the nVIDIA K1100M (also cut and change the wiring of the thermal sensors between the optical drive and the GPU heatsink). Reassemble the iMac, but leave all HDD/SSD disconnected.
5.) Boot the iMac from G.), expect a non-functioning screen. Access via ssh, flash the video-bios, and shut down. Disconnect the Linux USB drive.
6.) Power-on, and reset PRAM by holding Option+Command+P+R (https://support.apple.com/en-us/HT204063).
7.) Open up the iMac again, connect back any HDD/SSD.
8.) Boot High Sierra, confirm that the new video card is working (sleep/wake, brightness control, thermal).
9.) Install H.), apply necessary modifications, etc.

Questions:
Q1.) Does this look OK? Can you spot anything I concluded incorrectly? Or did I miss something?

Q2.) At step#8 with the iMac loading High Sierra, should the screen, sleep/wake, brightness control, and thermal just work fine? Or do I need to modify something in High Sierra's S/L/E, or use some form of OpenCore to boot my iMac at that point?
This is a late 2009 iMac 27, which is told to be seriously affected by the Black Screen problem, which requires the AppleBacklightFixup or an OpenCore parameter. What is not clear to me is if it applies only when I try to boot Catalina, or if High Sierra is also affected. Also, does this only apply to nVidia cards marked with double plus (++)? Because the K1100M I have is marked with a single plus (+). Some posts refer to this with reference to Metal capable GPUs, but the K1100M is not Metal capable.

Q3.) Will temperature detection and internal fan control correctly work on the K1100M card?
Do I need to cut and change the sensor wires as indicated in step 4.), or the K1100M does not require such changes? I have difficulty understanding the source of this thermal sensor problem. As far as I can see, there is a thermo-diode glued to the GPU heatsink. Why would that stop providing the correct temperature readings when the card on the other side of that heatsink is replaced. And why would another thermo-diode of the same kind (the one glued to the optical drive) would still provide the correct temperature. So why does cutting and swapping those wires solve anything?
How do I confirm the thermal sensor/cooling fan working properly?

Q4.) What macOS version can I upgrade to in step H.)?
Is Big Sur a recommended upgrade now? There was something about Big Sur very badly wearing down the SSD drives, has that been fixed with any of its updates? Is this true to Monterey too?
Are there any other issues with Big Sur or Monterey which would suggest that I am better staying with Catalina? Particularly with my 11,1 iMac hardware and a K1100M GPU.
 
Hey,

this thread is about replacing the GPU, not about baking it. So your posts are really off topic here.

Please open another thread about this story. Please understand that we will not and cannot handle and respond all possible problems related to and all upgrades possible with this iMac family. Search around, there are still hundreds of threads about your system type.

The most common threads cover installing and maintaining Mojave, Catalina, Big Sur and Monterey, replacing the drives and BT/WiFi cards and much more.
 
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