Coreboot on Lenovo x220 - Fix random system freezes

Keywords: Intel, Coreboot, Linux, random freeze

On the my Lenovo x220t (Intel i5-2520M) with Coreboot installed I notices that the system randomly freezes, which I could solve, by setting the intel_idle.max_cstate=1 kernel parameter in /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_idle.max_cstate=1"

The current set value can be read via

cat /sys/module/intel_idle/parameters/max_cstate  

This solved the issue for me, at cost of some battery time.