Macbook Pro 2011 white screen - can't install MacOSX I've recently tried to update my Macbook Pro late 2011 using dosdude's Catalina patches, as it is not officially supported. It worked fine, but after using it for a few days, it suddenly froze and crashed. I tried to restart it, got at the login screen but it would just try to sign in and freeze again on a white screen. I also have red horizontal lines in my screen. I have tried going to recovery mode, doing a SMC, doing a NRAM reset, going into safe mode, but nothing seems to work. I also tried the hardware test which told me there was no trouble. The internet recovery does boot up, but after entering my WiFi password it starts loading and eventually gets stuck on a white screen again. Even trying to use an installer USB get's till the point whether I would like to start from my Macintosh HD or USB, but after loading, it just freezes again.

I went to a even worse path by resetting the SSD, because I found some posts telling that the SSD might be corrupted. This means I have no backup unfortunately. 

What can I do to resolve this issue?

EDIT:

The comments suggested to record it. I have a image of the last logging (using verbose mode) that I could see before the screen went dark and started bootlooping.
Thanks to @Allan, I was able to find out how to solve my issue. I did the following:


I had another Mac's SSD be cloned using a program called carbon copy cloner to my Macbook's SSD.
I ran the High Sierra installer on that Mac, specifying the Macbook's SSD as final medium (this added a recovery HD)
Boot into single user mode to tweak the NVRAM using this guide, and this question was also very relevant.
Step 3 needs to be redone every time you update your OS. Note: your brightness function keys will also not work anymore!


Important command for temporary fix:

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


Transcript of the MacRumors thread in case it get's removed:

First of all, it is possible to successfully boot a MBP to OS X while still using the failed GPU, after you remove the AMD drivers by booting in command line mode (CMD+S) and entering these commands:
1) fsck -fy (to check a disk)
2) mount -uw / (mount a root filesystem with read/write permissions)
3) sudo mkdir /AMD_Kexts/ (make a directory to store the AMD drivers in case you'll need them in future)
4) sudo mv /System/Library/Extensions/AMD*.* /AMD_Kexts/ (move the AMD drivers)
5) sudo rm -rf /System/Library/Caches/com.apple.kext.caches/ (remove the AMD drivers cache)
6) sudo mkdir /System/Library/Caches/com.apple.kext.caches/ (just in case OS X will be dumb and will not recreate this directory, I am creating it for OS X)
7) sudo touch /System/Library/Extensions/ (to update the timestamps so that new driver caches - without AMD drivers - will be definitely rebuilt)
8) sudo umount / (umount a partition to guarantee that your changes are flushed to it)
9) sudo reboot