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NovaVI

macrumors newbie
Original poster
Oct 23, 2020
4
3
I have a MacbookPro 15" Retina mid-2012 going black screen whenever it switches to the dedicated GT650M NVidia GPU instead of the integrated GPU. This is apparently a well-knowned issue due to the bad solder joints of the U8900 power buck converter causing GPU VCore Failure. It has been documented by the infamous Louis Rossman for example (
).

I recently called a professional technician able to fix this issue. What he does is resolder the joints of this chip. But according to him, the fix is not stable, it can work two months and then the issue appears again.

Another technician told me it is a viable solution.

Could you tell me if it worked long-term or not for you ?

The stakes are 280€ not to be thrown out the window.

Any information would help !
 
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christiann

macrumors 6502
Jun 7, 2020
315
86
Laguna Beach, California
I have a MacbookPro 15" Retina mid-2012 going black screen whenever it switches to the dedicated GT650M NVidia GPU instead of the integrated GPU. This is apparently a well-knowned issue due to the bad solder joints of the U8900 power buck converter causing GPU VCore Failure. It has been documented by the infamous Louis Rossman for example (
).

I recently called a professional technician able to fix this issue. What he does is resolder the joints of this chip. But according to him, the fix is not stable, it can work two months and then the issue appears again.

Another technician told me it is a viable solution.

Could you tell me if it worked long-term or not for you ?

The stakes are 280€ not to be thrown out the window.

Any information would help !

Ugh, there is always some issue w/ the rMBPs. Some say reset PRAM.

here are two suggestions:

link 1: NVIDIA FIX: https://github.com/mayankk2308/purge-nvda

link 2: AMD fix?? http://www.javajirawat.com/2018/02/macbook-pro-2012-broken-gpu-work-around.h

link 2 says:
  1. "Boot into Recovery Mode
    For High Sierra 10.13.4 or earlier:
    Hold Command+R+S keyboard buttons while pressing the power button

    For High Sierra 10.13.5 or later:
    Command+R+S (Recovery mode Single-user) no longer works.
    https://apple.stackexchange.com/questions/332587/single-user-recovery-mode-on-high-sierra-10-13-6

    To get to Recovery Mode,
    * Hold Command+S and press the power button
    * On prompt, type command
    nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
    reboot
    * Hold Command+R to enter Recovery Mode GUI
    * Click on "Utilities" on the top menu bar and pick "Terminal"
    * Goto Step 2 below
  2. Disable System Integrity Protection (SIP)
    Type on the command prompt
    csrutil disable
  3. Reboot MacBook Pro into Single User mode
    Type on the command prompt
    reboot
    Then hold Command+S keyboard buttons
  4. Hard disk check
    Type on the command prompt
    /sbin/fsck -fy
  5. Mount root file system in read-write mode
    Type on the command prompt
    /sbin/mount -uw /
  6. Make a directory to save the AMD drivers
    Type on the command prompt
    mkdir /AMD_save
  7. Move AMD drivers to the save directory
    Type on the command prompt
    mv /System/Library/Extensions/AMD* /AMD_save
  8. Delete AMD driver cache
    Type on the command prompt
    rm -rf /System/Library/Caches/com.apple.kext.caches/
  9. Create AMD drive cache directory
    Type on the command prompt
    mkdir /System/Library/Caches/com.apple.kext.caches/
  10. Force refresh of drive cache and reboot
    Type on the command prompt
    touch /System/Library/Extensions/
    nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
    reboot
  11. Boot into Recovery ModeFor High Sierra 10.13.4 or earlier:
    Hold Command+R+S keyboard buttons

    For High Sierra 10.13.5 or later:
    See step 1 above
  12. Enable System Integrity Protection (SIP)Type on the command prompt
    csrutil enable
  13. Reboot MacBook Pro to normal mode.Type on the command prompt
    reboot
  14. Launch Terminal in UI and type
    sudo nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
  15. Restart MacBook Pro one final time"
Kind of the same proceedure w/ the bad Radeon in 2011 Macs..

i attempted this fix a while back, but try this first before you work on the logic board.

a replacement logic board might be best.. i wish apple still had that program.

lmk what you do..

-christian
 

NovaVI

macrumors newbie
Original poster
Oct 23, 2020
4
3
Hey Christan,
Thanks for the tools, it helped me a lot :)
So I tried several options on purge-nvda, especially "Suppress NVDA" and "AMD fix". They both fixed the instable GPU, but both came with the same drawback, I can no longer set up the brightness of the screen. This is apparently a known issue. I wanted to manually set up the AMD fix to see the outcomes but my laptop became too instable.
Have you heard of a solution concerning this brightness issue ?
Léo
 
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christiann

macrumors 6502
Jun 7, 2020
315
86
Laguna Beach, California
Hey Christan,
Thanks for the tools, it helped me a lot :)
So I tried several options on purge-nvda, especially "Suppress NVDA" and "AMD fix". They both fixed the instable GPU, but both came with the same drawback, I can no longer set up the brightness of the screen. This is apparently a known issue. I wanted to manually set up the AMD fix to see the outcomes but my laptop became too instable.
Have you heard of a solution concerning this brightness issue ?
Léo
Woo! On the GitHub it says “Use of this patch on applicable macs disables proper sleep and brightness controls completely, including the loss of clamshell sleep modes, that is, the display will not turn off even if the laptop lid is closed. Uninstall recommended for on-the-go use. I cannot investigate further workarounds, but I believe some Hackintosh solutions to enable sleep on iGPU might be applicable.”

It is a drawback but in the end soooo worth it.

have you tried Brightness Slider from the Mac App Store?
 

NovaVI

macrumors newbie
Original poster
Oct 23, 2020
4
3
Hello Christian,
Brightness Slider works very fine, it's a nice tool thanks :)
However as mentionned in the GitHub repo, I cannot come back from sleep mode. The screen is stucked on the background image, and doesn't print any connection input box. I have to reboot each time. So kind of a drawback, but still ok as I don't use my computer for work.
 

christiann

macrumors 6502
Jun 7, 2020
315
86
Laguna Beach, California
Hello Christian,
Brightness Slider works very fine, it's a nice tool thanks :)
However as mentionned in the GitHub repo, I cannot come back from sleep mode. The screen is stucked on the background image, and doesn't print any connection input box. I have to reboot each time. So kind of a drawback, but still ok as I don't use my computer for work.
Did I forget to reply?
 

NovaVI

macrumors newbie
Original poster
Oct 23, 2020
4
3
I did forget to reply ;)
No, I'm still considering to fix it by resoldering the joints since some bugs remain. But I'm kind of blind on the pros and cons of this solution.
 
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