1. Reboot Mac and enter to the Console mode (Command + S before gray screen appear)
2. mount -uw /
3. create folder example /_temp
4. move ale AMD folders (files) to folder you created
sudo mv /System/Library/Extensions/AMD*.* /_temp
!!!! 5. Execute command:
sudo kextcache -v 1 -m /System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /System/Library/Extensions/
This will rebuild kexts cache which won’t contain AMD drivers kexts
6. restart your Mac using – sudo reboot
7. Start your Mac normally – Mac should use only Integrated Graphics Card now and it should boot always using integrated gpu.
REALY IMPORTANT !!! Turn off any updates which are connected to Mac OS X !!! Any system update can break this state again. This fix worked for me. My mac was freezed completly. Now Im writing from it this post!