Unhappy [Q] G2 battery drain after updated to Android 4.4

Dear all, my G2 (Korean version, F320S) have massive battery drain after updated to Android 4.4.

For example, before that, the battery level dropped for only 1-2% when the phone was idling, even when I was using 4G networking. However, after updated, the battery level dropped massively (e.g. dropped 20% after 8 hours idling, using a 3G networking, like a Demand Curve).

Do anyone know how to fix this problem?