What processes are involved after system update shows upgrade available? Is it done OTA , and after downloading is complete what processes ensure proper upgrade?
If the update just keeps pausing or wont download then using the software and cable normally supplied with the phone, sync the phone to your computer and upgrade from there. I usually have to upgrade this way.
android recovery system should ensure that data not deleted while upgrading
Download OTA Update Center ,Read the GUIDE carefully to update your android phone OTA.
this app requires you to modify the system files.. So do it at your own risk
first backup the things in the phone.... update may be of two types firmware update in this your android version will remain same but updated to solve the bug and other problems.... other is firmware change and it will completely change your version of android
Downloading and installing updates requires internet connection.So,if it shows up in your phone and you install it,then it's OTA one.If it shows up in your PC suite software,then it's via desktop.
After the update gets downloaded,it can be installed afterwards.During installation,the device becomes unavailable even for emergency calls too.So,all the features gets blocked.
If you leave the phone during installation of updates,it does all of its works like installing updates,patching system files,optimizing apps for use etc..
if your phone shows that an update is available then it must be referring to an OTA. so just tap the message on the notification or go to settings>system update. tap on the update button to update to the latest firmware.