I have a mid 2014 Macbook Pro that is subject to the Random Shutdown issue and has been for some time now. This has been happening through many iterations of the Mac OS for a while now and still not fixed. I have sourced the instructions to work through the renaming of the AppleThunderboltNHI.kext file but Big Sur 11.1 does not allow you to rename. Says it's Read-only. I am attempting this after disabling csrutil and csrutil authenticated-root. I am restarting the machine in Recovery mode again before commencing the process of mounting disks and renaming the file. Any ideas on how to get past this renaming? If you can't do it and get rid of that file, the random shutdowns will continue.