Attention: Before you follow the instructions below, make a backup of your data in the internal memory of the device.
After updating the Motorola Razr i (xt890) for version 4.1.2 of Android, battery life was far below what was originally, from 6-7 days to 3 days in standby mode. A decrease of approximately 50% on a feature that was one of the device's strongest selling points.
To return the autonomy lost by update, I did something very simple, I used the Restore data factory function present in Setting-> Privacy. After selecting this function, the system will request confirmation alert on the level of the battery and restart the system itself. Wait until the procedure is complete, it can take up to 10 minutes.
At the end of the process the autonomy will be restored as can be seen in this screenshot.
Do not set all applications previously installed at once, do it slowly so you can identify some sucking battery app. So far I did not find any, but a little caution is desirable.
If this procedure work on your device, leave a comment.