2011 MacBook Pro booting to black screen

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2011 MacBook Pro booting to black screen

So, the story goes like this. I bought a secondhand 15 inch i7 2011 MacBook Pro yesterday. I picked it up locally, so I was able to see it working before paying the guy. I got it home and made a few minor hardware alterations (replaced HDD with SSD and upgraded the amount of RAM), which all went well and after making these changes the laptop was running perfectly.

I then go to set it up at my desk and connect it to my external monitor, and I run into my first problem. No signal detected at the monitor. I try a few different cables and different inputs on the monitor to no avail. It seems that there is nothing coming out of the mini Displayport.

To try and fix this issue I reset the NVRAM. I heard the two startup chimes indicating the NVRAM reset was successful, but since then I now can't get anything on the internal screen as well! I can hear the startup chime, and when it's "on" I can close the lid and see the little white light at the front indicating that it's powered up, but there's just nothing on the screen.

So far I've tried

-Resetting the NVRAM again

-Resetting the SMC

-Booting to Internet Recovery

-Booting in Safe Mode

-Undoing all the hardware changes I made

-Disconnecting and reconnecting the internal ribbon cable for the screen

Whatever I try, I'm now not seeing anything on the screen.

Any help at this point would be greatly appreciated!

MacBook Pro 15″, macOS 10.15

Posted on Jul 27, 2020 7:27 AM

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Answer 1

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JaffaJake88 Author

Level 1

9 points

Jul 30, 2020 1:59 AM in response to HWTech

OK, I have it working now! Thanks for the assist.

I'm not 100% on exactly why it started working, but I'll document the steps I took here in case it helps anyone else.

Following the instructions here: http://dosdude1.com/gpudisable, I booted (I assume) into single user mode with Command + S, and blindly typed in "nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00" and hit return. Nothing happened.

The next step is to reboot and go straight into recovery mode (Command + R) to run "csrutil disable" to turn of SIP, but with no GUI still I had no way of doing that.

So instead what I did was take the hard drive out and install it in another MacBook. Roll it back to Yosemite (the last version of the OS before Apple introduced SIP), and then pop that hard drive back in the problem laptop, and voila, hey presto, it fires straight up!

From there I then swapped the HDD with my SSD that has Catalina installed, and I'm now fully up and running (minus any sign of the dedicate GPU).

My best guess is that the command I sent earlier in single user mode gets cached somewhere until there's no SIP anymore, and then it gets written to the NVRAM at that point, but that's a bit of a stab in the dark, so if anyone has another explanation, I'd love to hear it.

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Answer 2

HWTech

Level 9

60,086 points

Jul 27, 2020 6:23 PM in response to JaffaJake88

First thing would be to reinstall the original memory. Macs can be very picky about the memory used so most contributors on these forums will only recommend using Crucial or OWC for memory (using the tools on their respective sites for identifying exact compatible part numbers).

The 15" model is known to have GPU issues. You can force the laptop to use the Intel GPU by using gfxCardStatus.

https://github.com/steveschow/gfxCardStatus/releases/tag/v2.4.4i

If you cannot boot macOS even in Safe Mode to install gfxCardStatus, then you can try these other methods in these links:

http://dosdude1.com/gpudisable

https://github.com/steveschow/gfxCardStatus

I'm not sure, but I believe if you force the laptop to use the Intel GPU that you may not be able to use the external display.

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Answer 3

JaffaJake88 Author

Level 1

9 points

Jul 28, 2020 7:44 AM in response to HWTech

Thanks for the reply. Very helpful!

The issue persists after swapping the RAM back over.

Reading into this GPU issue a bit more though, it seems that the nvram command to disable the dGPU can be undone with a PRAM reset, so I think that's exactly what must have happened here. Presumably at some point in the laptop's history somebody has applied this workaround, and I've gone and wiped it when I reset the PRAM.

Also, it looks like you're correct about the external display not working with the integrated graphics, so again that would be consistent with what I'm seeing.

Following the instructions here http://dosdude1.com/gpudisable seems my best bet, but the challenge for me now is to figure out how to input that command without being able to see anything on the screen! I've given it a try, but it hasn't made a difference. With nothing on the screen though, I don't necessarily know that it had booted into single user mode properly (Command-S on startup).

In fact, apparently Apple have disabled single user mode in Mojave and later, and this laptop is currently running Catalina (using dosdude1's patcher tool), so I'm not convinced that I'm booting to the right place to start with.

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Answer 4

HWTech

Level 9

60,086 points

Jul 29, 2020 6:02 PM in response to JaffaJake88

Check the links from the gfxCardStatus page which may contain alternate methods which may have you using a Linux boot disk to make the NVRAM changes. I'll see if I can remember to check my other computer for other links.

The settings will most likely be reset if a PRAM reset is ever performed.

See if you can actually boot into Single User Mode using the old method of using Command + S.

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2011 MacBook Pro booting to black screen

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