Samsung Note 2 battery drain issue resolved.

After the recent android update 4.1.2 for Samsung Note 2, lot of people are facing fast draining of battery and slow charging.
In fact, the battery performance dropped by 50% for many.

After looking around for various solutions online, the one that really works is to clear system cache.

1. Just switch off the phone.
2. Remove the battery for 1 minute.
3. Press the home button, volume up key together with power button.

The phone will boot in a black screen. Use volume keys for scrolling to options. For selection,  press power button.

4. Choose clear cache option and then reboot option.

Hopefully,  now the battery performance should come back to normal.