Purism posts directions on how to check if you properly installed coreboot and disabled IntelME here: https://puri.sm/coreboot/
Note: the information here is out of date, and cbmem output will be different. I have mentioned this to the Purism team and they said they will be updating this.
I went through these instructions when PureOS was on my machine, and everything went as expected.
I then installed QubesOS, and when going through these instructions again just to double check - I get the error:
No table found.
Is this expected?