http://blog.ptsecurity.com/2017/08/disabling-intel-me.html
I put quotes around "disables" because the ME is not fully disabled. The blog's analysis does show how it is in a "safe" state, i.e. forced to ignore the outside world very early in its code path. Also, not likely to brick your computer, assuming unscrewing your case and using a SPI flash programmer hasn't already bricked your computer.
Edit: "backdoor" in quotes too.