Totally bricked MacBook Pro 2011 A1286 - No recovery. What can I do?

I think my MacBook Pro is badly, badly bricked. Model is a1286

It's a really weird story.

This MacBook Pro had 2 partitions, one with Lion and the other was Windows but not accessible becouse was corrupted (if you tried to boot this partition, it would just show black screen and nothing happened).

BTW Lion was slow so I made a bootable USB and entered the recovery to do a fresh install of a new High Sierra system and I just erased the content of the Macintosh partition (the one targed Bootcamp was locked and didn't allowed me to erase).

It was ready to install a new system, but the bootable USB I made with High Sierra was not seen in the boot menu, that I entered pressing alt when powering on.

So I read in a forum that doing NVRAM reset could help, so I did, but the result was terrible.

Black screen and can't access to recovery or boot menu anymore.

I tried everything. I've also opened, and tried disconnecting the battery and the RAM and reconnecting them to see if changed something but nothing. Or powering up without the battery only with the power supply. Also tried to replace the HDD with another one formatted in HFS+ but nothing.

Now it just shows a black screen and does not recognize the commands.

If it can matter, the sound card is faulty and I used it with a USB one.

I've tried:

• Recovery pressing command + R

• Recovery pressing alt + command + R

• Boot menu pressing alt

• Nvram reset pressing alt + command + p + r

• SMC reset pressing shift + Alt + ctrl + power for 10/12 sec

The light of the USB bootable drive is always flickering when connected, but doesn't show nothing on screen.

Did I just destroy it?

The MacBook Pro in question is one of the infameous AMD Radeon 6750M GPU-equipped 2011 models. Apple set up a (free) repair program which ended in 2016.

Obviously the dGPU of this Mac died later and the dGPU/Mainboard weren't properly replaced. Instead an Apple certified? technician desoldered some resistors on the mainboard to disable the dGPU.

To get it working with the Intel-GPU nonetheless (= a monitor image) a special NVRAM parameter has to be set.

After resetting the NVRAM (and the SMC) this parameter was deleted which resulted in a black screen.

To get things working again the following was done:

1. Removing the partioned but empty HDD
2. Attaching the HDD to another Mac (external casing or USB-SATA cable). The 2nd Mac has to be capable of booting to a respective system (e.g. High Sierra, which is the last macOS for the early 2011 MBPs)
3. Install High Sierra on the external drive and boot to it
4. Configure ssh access (and Remote Desktop) in System Preferences > Sharing
5. Configure a network interface with an IP in the same IP-network as the working Mac
6. Detach the external drive and mount it in the MacBook Pro
7. Boot the MacBook Pro (and the working Mac) normally
8. ssh from the working Mac to the MacBook Pro
9. Enter: sudo nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00
10. Enter: sudo reboot or sudo shutdown -r now to reboot the MacBook Pro
11. Success!

If the HDD would have had a properly working system one could have omitted installing a new system.

These instructions helped a lot: Disable MacBook Pro Dedicated GPU

Installing and configuring MacBook Pro dGPU Disabler (as stated in the instructions) won't work, because the dedicated GPU wasn't recognized – as menitoned: the GPU was disabled in an incompetent manner previously.