MacBook Pro 2011 Defective GPU

Boot using Command + s. Press enter if the shell doesn't appear.

Disable discrete GPU: manually type nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00 and run it.

Manually type nvram boot-args="-v" and run it.

Reboot with sync; reboot.

Boot using Command + r (this time it boots fine, no grey screen).

Disable SIP: manually type csrutil disable and run it.

Manually type nvram fa4ce28d-b62f-4c99-9cc3-6815686e30f9:gpu-power-prefs=%01%00%00%00 and run it

Manually type nvram boot-args="-v" and run it

Reboot with sync; reboot.

Boot using Command + s.

Manually type /sbin/mount -uw / and run it.

Manually type mkdir -p /System/Library/Extensions-off and run it.

Manually type mv /System/Library/Extensions/AMDRadeonX3000.kext /System/Library/Extensions-off/ and run it.

Manually type touch /System/Library/Extensions/ and run it.

Reboot with sync; reboot.