Issue disabling Discrete GFX from Command Line in Macbook Pro 2011 High Sierra

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Level 1

4 points

Issue disabling Discrete GFX from Command Line in Macbook Pro 2011 High Sierra

As per the title I am attempting to disable the AMD discrete card so the machine uses only the integrated card. I originally went through the graphics card recall for this machine however as expected the replacement discrete card has now failed again. I can use gfxCardStatus to switch the cards after logging in if I can get that far. To actually log in however it is a lengthy cycle of restarts and reboots so the machine uses the integrated card after boot. I understand if I log in using the discrete and the machine gets as far as the white screen when user log in should complete and the machine restarts, the integrated card is defaulted at next boot. This isn't always the case however and I now need to disable the discrete card from the command line. I have gone through the steps of resetting PRAM and SMC.

The issue here is I cannot get the machine to enter single user mode using cmd rs. Now I know the file vault is enabled and I need to disable that however I cannot do that as the combination cmd s also does not work. Nor does entering via verbose mode (cmd v). In each case above I am presented with the screen attached for a quick few seconds and then the machine continues to boot to the log in screen. I am also not able to enter either internet or system recovery mode. I can get to the spinning globe, connect internet and upon progress bar completion the machine hangs. I can run a hardware diagnostic and this returns no issue.

I feel my issue is relating to the file vault as that seems to be the first error returned from the screen attached. I would be grateful if someone has experience or knowledge of such issues could take a look at the attached and discern what appears to be occurring here and a possible work around to disable the discrete card and default the machine to booting up using only the integrated card.

Feel free to ask any further information you need and I am grateful in advance for any insight or possible solutions here.

MacBook Pro 15″, macOS 10.13

Posted on Nov 9, 2021 4:17 AM

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Answer 1

Nov 13, 2021 1:37 PM in response to rsimon86

If you cannot even boot into Safe Mode, then you can try forcing the laptop to use the Intel GPU using these instructions which sets an NVRAM setting:

http://dosdude1.com/gpudisable/

I've also seen instructions to use a Linux boot disk to set the NVRAM setting as well since Linux may be able to boot the Mac without using the discrete GPU unlike macOS.

There is a possibility your GPU is such that it is actually affecting the booting of the Mac as well. I do know that the GPU issue presents itself in ways that don't involve the screen itself.

Filevault should not be a problem unless you have some corruption on the drive that is preventing Filevault from unlocking or more likely there is file system corruption that is preventing the volume from mounting once it has been unlocked (I've seen the latter several times).

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Answer 2

Nov 17, 2021 10:40 PM in response to rsimon86

It appears it is unable to unlock the Filevault due to an issue accessing the encryption keys. Unless you have a Filevault Recovery Key from when you enabled Filevault you will not be able to unlock the Filevault if the encryption keys located on the drive are corrupted or damaged. You can try accessing the drive using another Mac to see if the drive can be unlocked and mounted. The Filevault issue is not the main problem although it may be another symptom.

You can try reseating the memory modules in case one of them is loose and you can try using just a single memory module in case one module or slot is bad. The memory slot nearest the Bottom Case tends to fail more often due to cracked solder joints. If you recently upgraded the memory, then perhaps the memory is not compatible.

Since Filevault cannot be unlocked you will not be able to boot into Single User Mode. You should try using Internet Recovery Mode (Command + Option + R) to try to disable the discrete GPU.

You can also try running the Apple Diagnostics to see if any hardware issues are detected.

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Answer 3

BDAqua

Level 10

250,773 points

Nov 9, 2021 2:18 PM in response to rsimon86

I imagine you;ve seen this...

gfxCardStatus is a free menu bar application that keeps track of which graphics card your MacBook Pro is using at any given time.

https://gfx.io/

You can force a Macbook Pro to use the Integrated intel graphic via gfxCardStatus

.

The above does not work on Sierra and beyond, HOWEVER, this version works on High Sierra:

https://discussions.apple.com/message/32581726#32581726

https://github.com/steveschow/gfxCardStatus/releases/download/v2.4.4i/gfxCardStatus.app.zip

Click the MacOS installer icon -> continue holding the Command + S keys until you finish the MacOS installer Single User boot .

Enter these commands (change gpu-power-prefs to Intel GPU and boot verbose):

Code:

nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00

nvram boot-args="-v"

reboot

https://forums.macrumors.com/threads/force-2011-macbook-pro-8-2-with-failed-amd-gpu-to-always-use-intel-integrated-gpu-efi-variable-fix.2037591/

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Answer 4

Nov 20, 2021 8:08 AM in response to rsimon86

rsimon86 wrote:

I have also run apple diagnostics multiple times and no issues are detected.

Unfortunately a diagnostic is really only useful when it detects a problem or when it freezes when running. If the GPU is bad again, then the diagnostic may not be able to detect the failure. Apple had a special service diagnostic which attempted to detect the GPU failure, but even that specialized diagnostic would not detect some of those GPU failures.

While the issue appears to most likely be GPU related we cannot entirely rule out a memory issue.

If you need to access the data on the drive you can try removing the drive & connecting the drive to another Mac to see if you can unlock & mount the drive. This will only work if the laptop itself is the reason Filevault could not be unlocked.

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Answer 5

rsimon86 Author

Level 1

4 points

Nov 11, 2021 6:02 AM in response to BDAqua

Thank you for your reply.

I was able to install gfxCardStatus initially and if the machine boots using the integrated card and logs into the user account this application runs immediately and switches the card. The issue recently is each time I boot the discrete card is being used whilst previously the machine would boot with the integrated every 3-4 combinations of being forced to hard shutdown. At this point I am unable to boot into the recovery mode or internet recovery mode as after the bar has filled almost completely full the screen goes blue and a hard shutdown is required. Attempting to boot into single user mode or verbose mode I am presented with the green screen of text attached above.

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Answer 6

BobHarris

Level 9

57,331 points

Nov 11, 2021 12:05 PM in response to rsimon86

gSwitch is another utility (newer than gfxCardStatus) lets you set which graphics card your macbook pro can use, mainly to prevent it from using the discrete graphics card

https://codyschrank.github.io/gSwitch

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Answer 7

rsimon86 Author

Level 1

4 points

Nov 17, 2021 6:45 AM in response to HWTech

Thanks for your reply.

Unfortunately I cannot disable the card via the terminal as when I attempt to boot into single use mode or verbose (command s, rs or v) I am presented with the green screen above.

Your third paragraph makes sense as I do feel there has been a change in the hardware where the GPU itself is now causing an issue on boot that was not there previously. I was at one point able to eventually boot the machine up with the integrated card enabled whereas now the machine boots with the discrete card every single time.

Looking at the green screen above, can you see code that relates to where the system is failing? Following that screen the machine loads through to the user login but from there attempting to log into either my account or the guest account eventually resolves to a white screen.

Thanks for your input here.

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Answer 8

BDAqua

Level 10

250,773 points

Nov 11, 2021 8:33 AM in response to rsimon86

She's dead Jim! :(

Just as a test & possible way to get your data off, hold t key on powerup to see if Target Disk Mode works... do you get a big floating symbol?

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Answer 9

rsimon86 Author

Level 1

4 points

Nov 11, 2021 8:52 AM in response to BDAqua

I do yes. The screen is also unchanged and it appears to be using the discrete card so I am now thinking somehow the integrated card has also failed as entering target disc should use the intel card.

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Answer 10

rsimon86 Author

Level 1

4 points

Nov 19, 2021 6:22 AM in response to HWTech

Thanks for your reply.

This is what I suspected. I have a feeling the inability to unlock the file vault could be related to corruption through repeat hard reboots and shutdowns. This could also be locking the discrete card as default on each boot.

The machine has not been recently upgraded. Initially the issue occurred with the discrete card, this was repaired under recall program and now it appears a similar issue has happened again with the card.

Internet or regular recovery mode does not work either. The loading resolves to a blue screen with black lines in each case where a hard reboot is necessary.

I have also run apple diagnostics multiple times and no issues are detected.

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Issue disabling Discrete GFX from Command Line in Macbook Pro 2011 High Sierra

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