Upgrading Android from 4.2 to 4.4 on Lenovo Tablet B6000-HV I have tried and failed to upgrade from Android 4.2 to 4.4 on my Lenovo B6000-HV. At first using OTA method; Error in the middle of process and I have to flash with stock ROM to make it working again. Then I tried to put the files on micro SDcard; The error was failed to update.
Method 1:

Go to Recovery and Clear cache and Dalvik.

Reboot and Check for OTA. 

Update it.

Method 2:

Backup all data to any external storage (Apps and data).

Factory Reset device.

Check for OTA.

Update it.

Restore Data.

Method 3:

Install Custom Recovery and Custom Kitkat ROM from XDA.

Custom Recovery

Custom ROM