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

[caxias_Brazil]

https://www.ebay.com/itm/5YPW3-9R3F...182286?hash=item3fcae89ece:g:XCwAAOSwGW1daY2m

Also read through the very beginning post on this thread.

thanks, sir!

 

[FlorisVN]

great update again Nick !
using your bootrom beta 2 patch, makes all the diagnostic leds on the logic board work like you said.
which makes it an ease to use for testing, when using this new bootrom patch you now know if your mod works without having to reassemble the iMac display again..

keep it going !

Now a few more small fixes which need to be fixed somehow, some day if possible :
- built in screen brightness control (hardware and or software fixes are available for this )
- bootscreen delay fixes, at least for Nvidia Kepler cards, I have not tested it with AMD cards
- fixes for sometimes EFI screen not showing up after a reboot ( I have not seen this myself yet)
- fixing target display mode, and if possible even better apply true display port signals instead of thunderbolt.

little fun fact perhaps, I just ran an Apple EFI diagnostic test, and all past just fine
this was with an upgraded GTX765m with custom bios and bootrom patch.
the EFI test also did some checks on the bootrom, and all past just fine..

 

[Mr-Mur]

great update again Nick !
using your bootrom beta 2 patch, makes all the diagnostic leds on the logic board work like you said.
which makes it an ease to use for testing, when using this new bootrom patch you now know if your mod works without having to reassemble the iMac display again..

I am looking forward to perform this operation myself!)

By the way, when progamming EeepROM, what kind of chip do you in programmer software? I didn't find a 100% match for our chip

 

[FlorisVN]

I am looking forward to perform this operation myself!)

By the way, when progamming EeepROM, what kind of chip do you in programmer software? I didn't find a 100% match for our chip

I presume you mean the Eeprom of the iMac, for the bootrom patch ?
My chip says : 25L6406E

So i've added the following command with flash rom -c "MX25L6406E/MX25L6408E"

your chip is not in the list ?
I think flash rom also works with auto detecting.. ?

 

[Mr-Mur]

I presume you mean the Eeprom of the iMac, for the bootrom patch ?
My chip says : 25L6406E

So i've added the following command with flash rom -c "MX25L6406E/MX25L6408E"

your chip is not in the list ?
I think flash rom also works with auto detecting.. ?

I am going to flash with a Windows GUI tool like CH341A Programmer it has not Macronix' chip set.
But! AsProgrammer has already, maybe I will flash with this tool

 

[Mr-Mur]

By the way, did you desolder iMac chip? Or it is safe enough to flash using a clip?

 

[Roman78]

I got BootROM version IM121.0047.B29 on my 2011 running High Sierra.

 

[iGermannn]

I got BootROM version IM121.0047.B29 on my 2011 running High Sierra.

View attachment 856868

What is your GPU model?

 

[Borak]

I replaced the 770m with another 770m and the imac worked normal. Maybe some issue with the first card.

I didn't install anything. It was plug and play. I lost the initial screen and the contrast control.
I just need to hit the power button 2 or 3 times.
Do I need to do any other procedure?

 

[Borak]

The Radeon HD 6970M - iMac Mid 2011 - EMC 2429, is compatible and run in iMac Mid 2010 - EMC 2389?

Thank's!

 

[jmilan0302]

The Radeon HD 6970M - iMac Mid 2011 - EMC 2429, is compatible and run in iMac Mid 2010 - EMC 2389?

Thank's!

Yes, it should work but it won't for long because all the AMD cards break eventually.

 

[FlorisVN]

I got BootROM version IM121.0047.B29 on my 2011 running High Sierra.

View attachment 856868

I would advise you to upgrade to booteom : 87.0.0.0.0
I have done by doing a high sierra 10.13.6 clean install, and updated to the 004 security update.
This update took a long time to install, but also did an efi update which gave me bootrom : 87.0.0.0.0
[doublepost=1568057520][/doublepost]

By the way, did you desolder iMac chip? Or it is safe enough to flash using a clip?

I just used a clip, was working fine for me.
Ive just used it again today with succes for the beta2 bootrom mod from Nick.

But like nick stated these clips are not the best, cleaning is sometimes neccecary..
They are I think also not made for lots of use..

 

[Nick [D]vB]

By the way, did you desolder iMac chip? Or it is safe enough to flash using a clip?

Please don't de-solder the chip! The test clip works fine on the bootrom, but DON'T use the normal CH341A windows software, I have had big problems with it on larger EEPROM chips. It is very slow (can take hours!) and normally gives write errors. If you must use windows then use the Flashrom version I posted a few pages back instead, just remove the old CH341 drivers and manually install the included driver through device manager.

Now a few more small fixes which need to be fixed somehow, some day if possible :
- built in screen brightness control (hardware and or software fixes are available for this )
- bootscreen delay fixes, at least for Nvidia Kepler cards, I have not tested it with AMD cards
- fixes for sometimes EFI screen not showing up after a reboot ( I have not seen this myself yet)
- fixing target display mode, and if possible even better apply true display port signals instead of thunderbolt.

Great to hear you got the Beta 2 bootrom flashed ok. I think target display mode might actually work now, with thunderbolt on the 2011 or DP on the 2010, enabling DP input on the 2011 would be great if it were possible.

I do have a partial fix for the boot-screen problems. I always get the “instant” boot screen on my Windows drives, with legacy or UEFI mode (and on my NVME adapter). I never install Windows using Bootcamp assistant but I do install the Bootcamp Control Panel for the boot drive selector, and that is the critical part. When you select the Windows drive (click Apply then click Restart), you always get the instant white screen & it boots in a few seconds, then it stays working consistently, even after a cold start from shutdown (with AC unplugged).

I did most of my tests switching between Windows and Mojave, with windows as the default boot disk, which is why I didn’t really notice the problems myself. I found that after using Bootcamp control panel if I then removed the windows drive and swapped in a MacOS drive it would not boot, you get a black screen with white text saying “no bootable device”. A NVRAM reset fixes it, so there must be an NVRAM variable, which means that setting the equivalent variable for the MacOS drive should fix the boot-screen problems - even without windows installed.

I'm looking into it.

 

[T'hain Esh Kelch]

My Radeon 6970M failed for the third time today. First bake lasted 23 months, second bake 6 months. Will redo it tomorrow again, but it likely wont last long before it is completely dead.

 

[Borak]

Yes, it should work but it won't for long because all the AMD cards break eventually.

Which GPU Nvidia GTX can you indicate?

 

[LegoNickD]

Hate to get a bit off topic for a bit, but its kinda related. I successfully upgraded my 2010 27" iMac from an i3 5-something to a Xeon X3470. This has the known effect of reporting as an i3 in About This Mac, does anyone know how to edit the About This Mac screen? I've tried to google it but everything is for hackintoshes or older OS X. I will upgrade to a GTX 765m or RX 460 depending on if there is a light at the end of the tunnel for backlight. Great work on the bootrom Nick!

 

[Roman78]

What is your GPU model?

On this one it is the K1100M

 

[TheElectrocat]

Backlight Control

Background:
The 2011 iMac display backlight system uses pulse-width-modulation (PWM) to control backlight intensity. A PWM control signal is generated within the logic board-video card circuit and routed to the PWM input on the backlight board. The PWM frequency is 13KHz and the pulse height is 3.25V. The duty cycle is varied from 0 to 100% to adjust backlight intensity from minimum to maximum. When a non-Apple video card is installed that lacks a proper EFI, the logic board-video card circuit outputs a duty cycle of 100% resulting in maximum backlight intensity which reduces contrast and generates extra heat. The solution is to isolate the logic board-video card and backlight board circuits from one another (cut the wire that connects them) and feed a desired duty cycle PWM signal into the backlight board PWM input using a low-cost PWM module based upon the Texas Instruments TL494 IC.

You will need the following supplies:
1. TL494 PWM module (purchase from Amazon)
2. Wire (black for ground, red for 12V power, and 3rd color for PWM signal)
3. 1/4W Resistors – 1 x 1.8K and 1 x 6.8K

You will need the following tools:
1. Oscilloscope that has a bandwidth of 15KHz or greater and can measure frequency
2. Multimeter
3. Soldering iron and solder
4. 12V DC power supply

Step 1:
Solder the 1.8K resistor to the “OUT” pin, solder the 6.8K resistor to the “GND” pin adjacent to the “OUT” pin. Solder the other end of each resistor together. Note: This creates a voltage divider that reduces the output of the PWM module from 5V peak-peak to the backlight board required 3.25V peak to peak. The PWM output will be the connection between the two resistors and this will be fed to the PWM input on the backlight board.
View attachment 809421

Step 2:
Connect the positive power supply lead to the “VCC” pin and the negative power supply lead to the to the “GND” pin adjacent to the “VCC” pin. Connect your oscilloscope to the PWM output and it’s adjacent “GND” pin. Adjust the two potentiometers on the PWM unit to achieve a frequency of 13KHz and duty cycle of 50%. Note: This will achieve a backlight intensity of 50%. If you want higher or lower backlight level adjust duty cycle accordingly.
View attachment 809422

Step 3:
Remove backlight board and disconnect all connectors. Solder wires onto the board as pictured. Note:Red wire is 12V DC power, black wire is ground, and blue wire is PWM signal.
View attachment 809423
View attachment 809424

Step 4:
Identify which wire is carrying PWM signal from logic board to backlight board and cut this wire on the wiring harness: Look at the female connector on the backlight board and identify the pin on the connector that is soldered to the blue wire. Look at the male connector on the wiring harness that connects to the backlight board to the power supply and identify the corresponding pin. Locate this wire and pull it through the sleeve on the wiring harness to identify which wire needs to be cut. Once cut, use multimeter on ohms setting to confirm the correct wire is cut. Note: Where the backlight board wiring harness connects to the power supply you will see two wires that don’t connect to the power supply but travel onward in the harness to the logic board. One of these is the “PWM signal” wire and the other is the “Backlight ON” wire.
View attachment 809425
View attachment 809426

Step 5:
Install PWM module, route wires, and solder wires to PWM module as pictured. Note: The red wire goes to the “VCC” pin, the black wire to the “GND” pin, and the blue wire to the PWM output lead between the two resistors created in step 1.
View attachment 809427
View attachment 809428
View attachment 809429

Step 6:
Reinstall LCD screen but do not yet install the LCD screws. Power on and boot iMac into macOS and adjust brightness with Brightness Slider App to determine if the range of brightness adjustability is where you want it. You can adjust potentiometer labeled D to increase or decrease the duty cycle to adjust the maximum backlight level to your liking (the potentiometer labeled “F” adjusts the PWM frequency – be careful not to change it). Reinstall LCD screws and screen glass. Congratulations - you’re done!

thanks for the information, i search for macbook pro pwm control solution and this is the begin.

 

[Zulus555]

I do have a partial fix for the boot-screen problems. I always get the “instant” boot screen on my Windows drives, with legacy or UEFI mode (and on my NVME adapter). I never install Windows using Bootcamp assistant but I do install the Bootcamp Control Panel for the boot drive selector, and that is the critical part. When you select the Windows drive (click Apply then click Restart), you always get the instant white screen & it boots in a few seconds, then it stays working consistently, even after a cold start from shutdown (with AC unplugged).

AND AGAIN MY RESPECT! Let me remind you that I only have the Windows system installed. Will installing the bootcamp application help me get the boot screen without the bootrom patch?

 

[FlorisVN]

AND AGAIN MY RESPECT! Let me remind you that I only have the Windows system installed. Will installing the bootcamp application help me get the boot screen without the bootrom patch?

nope, a bootrom patch and vbios mod for Nvidia cards are necessary atm to get a bootscreen as far as I know..

 

[Bacci]

Excellent work to have the option of a boot screen on the Kepler cards, but I'm gonna pass on opening my iMac again just for that. With screen sharing as first and Target Disk Mode as last resort (works regardless of graphics card, even if screen is black) there's always a fix. Let's hope Catalina isn't the last OS X we can run with our Kepler cards.

 

[FlorisVN]

Excellent work to have the option of a boot screen on the Kepler cards, but I'm gonna pass on opening my iMac again just for that. With screen sharing as first and Target Disk Mode as last resort (works regardless of graphics card, even if screen is black) there's always a fix. Let's hope Catalina isn't the last OS X we can run with our Kepler cards.

I did not got target disk mode to work before, without an EFI bootscreen.
With these mods I am now able to use target disk mode..

Nick also released a vbios to enable EFI on AMD RX580/RX560 cards btw..

And indeed even if Kepler will die, which I think also won't for at least a few more years.
we can use these AMD cards, which will have a lot longer live left for MacOS..

 

[FlorisVN]

just letting you all know.
using the bootrom patch from Nick, will give you the MacOS EFI check dialog warnings (since High Sierra).

I spoke about this with Nick, and he is aware of this but nothing major to worry about.
MacPro users with modded bootroms also got this message.

Anyway like Nick said to me, it is possible to disable this efi checker within macOS.
I don't know as of yet, but perhaps someone else here knows how, and can share it here also..

I want to search for a solution not getting bothered with this message anymore in the future..

 

[Mr-Mur]

Nick!

It works excellent, dear pal! Report later

 

[Borak]

Please, i want any informations.

I installed the 770M on iMac 27 "Mid 2011.

Everything went well during the installation.

I lost the boot screen and bright control.

I'm a light user and I don't understand command lines.

Questions:

1 - To start I need to press the power button 2, 3 times. what could be causing this?

2 - When starting sleep mode the iMac does not return. I think shut down because the caps lock key doesn't work.

3 - Do I need to install any software for brightness control?
Can I have it natively?

4 - Is it possible to have the boot screen again easily?

What procedure to work everything 100%? Step-by-step, please!

Thank's!