I have the same problem, almost the same configuration:
$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date 66CN55WW 02/28/2013
$ uname -a Linux yoga 3.13.0-38-generic #65-Ubuntu SMP Thu Oct 9 11:36:50 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
I must add that I use Ubuntu 14.10, except for the kernel which I kept from an older ubuntu version (because of the Yoga's wifi card, other problem)
I have the same problem, almost the same configuration:
$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
66CN55WW
02/28/2013
$ uname -a
Linux yoga 3.13.0-38-generic #65-Ubuntu SMP Thu Oct 9 11:36:50 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
I must add that I use Ubuntu 14.10, except for the kernel which I kept from an older ubuntu version (because of the Yoga's wifi card, other problem)