Backup / Upgrade OS

[Polterry]

My Lenovo Tablet has full instructions for upgrading OS from 4.4.2. I am however a bit nervous and I would like to know

1. Can I back up OS before upgrade
2. If there are problems with upgrade will I be able to convert back to original

If the answer to both above is yes then some general guidance on how to proceed would be appreciated

 

[Hadron]

The answer to 2 depends on the manufacturer, which I can't answer for Lenovo. But the answer to 1 is no, unless you have a custom recovery in which case the official over-the-air update doesn't work on most devices (if you don't know then you don't have a custom recovery).