[coreboot] Experiments with disabling the ME on Sandybridge x230

[Trammell Hudson]

I'm experimenting with what happens if I remove the ME firmware from
from the lower SPI flash chip on my Thinkpad x230.  If I just erase the
first 4KB of its region (0x3000, starts with "$FPT"), coreboot boots up
fine and reports that "WARNING: ME has bad firmware".  My Linux payload
initializes without any complaints.

The boot script then kexec's into Xen and Qubes, which works, but things
like S3 sleep don't seem to kick in when I close the lid ("unknown key
pressed", code e058).  systemctl suspend works fine and the system wakes
up when I open the lid again, so this might might be a spurious issue.

If I erase the entire ME region from 0x3000 to 0x4FFFFF the system will
not boot at all.  The indicator on the power button will flash when
I press it, but the system does not seem to respond otherwise (I do not
have a port 80 debugger or hardware serial port to see where it is
failing).  Reflashing with the original ME firmware restores it's
functionality.

-- 
Trammell