Well, it definitely is the ME that's the problem if it switches off after exactly 30 mins. That *should* be the correct way, yes, assuming you have the right image for the right Chromebook model (which it's possible you don't considering what's happening).

With Acer Chromebook's (and sometimes other makes, HP springs to mind) there can be several different versions of the same Chromebook model, which might ostensibly look the same, but are actually running a different chipset (Broadwell vs Baytrail vs Skylake vs Braswell).

I would suggest you post the exact model number and image name you downloaded so this can be verified.

I have a new acer chromebook I have flashed with coreboot + seabios payload. It boots to linux ok, but then powers off suddenly after 30 min regardless of whether I am using it. 

I disabled hibernation and have been leaving it plugged in, but this changes nothing. I suspect a faulty intel me since there is nothing else I can think of. The strange thing is I did not use me cleaner but used the full me extracted from the original bios. Later I downloaded the stock chrombook bios for my model from google and extracted the me module from that. 

At this point I have built several variations of roms using the me module from the original bios, the google bios, and "cleaned" versions of both but always with the same problem of power off after 30 min.

I am confused as to what the problem may be. I used the intelmetool bundled with coreboot but when I run it with the -s flag it seg faults.

In order to extract the me rom I used ifdtool that is included with coreboot.

./ifdtool -x bios.bin 

The intel me module is found at offset 00001000 - 001fffff and is 2 mb in size. Is that the correct way to do it? 

Any suggestions would be appreciated.