Yes, this is one of the best ways of making sure that an update is as good as it can be on your phone. Or just sorting out various issues.
But I don’t want to lose all my phone contacts!
One of the new things in the Marshmallow update is that backup now is done directly to Google servers. i tried it and it worked just fine for me. backed up what I needed back. Didn’t have to setup my mail accounts on my M8 and so on. Yes, it saved my messages as well.
So, just make sure that you’ve set Backup my data to ON under Settings > Backup & reset
I really recommend that you keep all your contacts as google contacts as well
If you don’t got your phone setup that way, you can easy do it in People > 3 dot menu > Manage contacts > Copy contacts, where it will ask from where to copy and then to where.
You’ve got two ways in doing a Factory reset.
Open Settings > Backup & reset > Reset phone, will warn you about what it will remove. And, on the bottom part of it you have a tickbox for Erase SD card, which you of course might want to avoid if you want to keep the content on the card.
Via hardware buttons on phone
- Power off phone
- Press and hold Vol down , press power button until you see bootloader (3 happy androids on skateboards at bottom of page). Release vol down.
- Select Factory reset, and just go with it.
And a third way that I almost forgot about
When wiping the cache partition, there’s an option for factory reset there as well.
So, how do I get my stuff back after the factory reset?
Just follow the guide when your phone reboots after the reset, and it will ask you what to restore from.