Updating iMac 17,1 Late 2015 to Monterey from Catalina has fried my GPU...I think.

This iMac was in the process of an update from Catalina to Monterey an

d near the end of the update, the fan seemed to run at full speed for

a while until it just crashed and when it restarted, it said there had

been a failure and had to shut down. I’ve gone through every process

the internet possibly has to offer over the past few days and I’m almo

st certain the update has cooked the GPU!

It only boots in safe mode, normal mode never loads fully, it always j

ams ALMOST there on the black screen with apple logo and progress bar.

Occasionally it will stretch the scaling of the load screen all over

the place or there will be some artifacting on the progress bar in the

form of small black horizontal lines, and it’ll freeze even further l

eft on the prog bar. I’m praying it’s just a firmware/driver issue wit

h the GPU as it’ll mean a new logic board otherwise!