MBP 2011 15" won't boot, NVRAM key combination causes loop

[kohsamui100]

My 2011 MBP has the notorious GPU issue, which I've worked-around using the methods suggested in the forum (disabling one GPU). But suddenly, it has a new issue. It wouldn't boot to the apple logo at all, or it would show the logo, start load the OS and then shut down. When it doesn't boot, it also doesn't play the apple startup sound...

- Pushing the NVRAM clearing key combination and holding it like this, it would boot with the sound, and then do that again and again in an infinite loop (i.e playing the startup sound)
- Clearing SMC didn't help
- Disconnecting the SATA drive didn't help

Any suggestions please?

 

[zfrogman]

My 2011 MBP has the notorious GPU issue, which I've worked-around using the methods suggested in the forum (disabling one GPU). But suddenly, it has a new issue. It wouldn't boot to the apple logo at all, or it would show the logo, start load the OS and then shut down. When it doesn't boot, it also doesn't play the apple startup sound...

- Pushing the NVRAM clearing key combination and holding it like this, it would boot with the sound, and then do that again and again in an infinite loop (i.e playing the startup sound)
- Clearing SMC didn't help
- Disconnecting the SATA drive didn't help

Any suggestions please?

Hi,
Although almost late January 2020, I came across your post while searching for a MBP 2011 topic. I don't know what version of OS you have (Catalina, Mojave??) but I can confirm that Catalina 10.15.2 runs very smoothly (with some minor limitations regarding the non-metal aspects of the GPU). Use Dosdude's excellent patcher and you should not even have to do the disable-via-software process you describe. Hope this helps. http://dosdude1.com/software.html. BTW you can find some great advise and info on the https://forums.macrumors.com/threads/macos-10-15-catalina-on-unsupported-macs.2183772/. bye

 

[kohsamui100]

Thanks! My MBP held well with the hack for a few years now, but recently has just died.

 

[zfrogman]

Thanks! My MBP held well with the hack for a few years now, but recently has just died.

No problem. BTW I do keep "in reserve" the command line process shell script to disable the dGPU just in case. This because if your dGPU is already failing and you need to reset PRAM fro some reason, you can still access command line instructions screen at bootup (CMD+S/CDM R+S). For this, you should put the shell script "force-iGPU-boot.sh" mentioned in the command line process instructions inside the root Macbook Pro (in Catalina there are now 2 "root" directories: MacBook Pro and Macbook Pro -Data as Catalina separates the macOS from your data and applications). This as a backup to restore the NVRAM process in case you need to reset PRAM which actually can negate the command line NVRAM dGPU bypass as well as dodude patcher setup of Catalina (i.e you will get the weird color/zagged characters screen). As you know, the shell avoids the lengthy line by line command instructions. When you use the Dosdude patcher there is no longer a need to create a Extensions-off in System/Library although it doesn't harm the Dosdude process to keep it. Keep in mind also that if you need to reinstall MacOS Catalina via Dosdude patcher, it will delete the shell script from the Macbook Pro root and the Extensions-off so you will need to re-insert the script. (The loginhook in /Library doesn't get deleted however if reinstalling with the Dosdude patcher) Hope this makes sense and helps. Bye

 

[rcoden]

My 2011 MBP has the notorious GPU issue, which I've worked-around using the methods suggested in the forum (disabling one GPU). But suddenly, it has a new issue. It wouldn't boot to the apple logo at all, or it would show the logo, start load the OS and then shut down. When it doesn't boot, it also doesn't play the apple startup sound...

- Pushing the NVRAM clearing key combination and holding it like this, it would boot with the sound, and then do that again and again in an infinite loop (i.e playing the startup sound)
- Clearing SMC didn't help
- Disconnecting the SATA drive didn't help

Any suggestions please?

Dang, I have the exact same model, same solution for the GPU, and now the exact same issue with the power, and either no sound, or start up sound on a loop. If you find a solution, please share.

 

[zfrogman]

Dang, I have the exact same model, same solution for the GPU, and now the exact same issue with the power, and either no sound, or start up sound on a loop. If you find a solution, please share.

Hi this older post in unsupported mac forum might help
#6,885

cheers