Root Sprint] galaxy S3 question about updating rom from 4.1.2

[congaman59]

I am running a 4.2.1 (stock rom) MK something or other. I would like to upgrade to 4.4.2. I have been told previously it would be best to go back to (un-root) state before I upgrade I suppose that still holds true?
I have a stock kernel as well and flashed the rom I have with Kies. It was suggested I flash
ND8 Kitkat ROM. Because I can't get the phone to update at all. I haven't done anything with the phone rom wise for quite a while now.
I suppose the best thing to do first is a nandroid back-up I am not sure exactly what that is. I have a backup of all the files on the phone on my laptop. I heard on here someone say something about (Helium) is that something I can use to do the back-up? If not how do I do the nandroid? Oh and I have titanium back up pro on the phone. I have some of my apps on the SD card with (GL to SD). How do I back up those apps? Or do I need to? I went to XDA to see about downloading ND8 and the link was bad! I'm open to suggestions on what my next move should be. I'm the kind of person that likes good step by step instructions on these kind of things so I don't brick my phone.

 

[Madbat]

I am running a 4.2.1 (stock rom) MK something or other. I would like to upgrade to 4.4.2. I have been told previously it would be best to go back to (un-root) state before I upgrade I suppose that still holds true?
I have a stock kernel as well and flashed the rom I have with Kies. It was suggested I flash
ND8 Kitkat ROM. Because I can't get the phone to update at all. I haven't done anything with the phone rom wise for quite a while now.
I suppose the best thing to do first is a nandroid back-up I am not sure exactly what that is. I have a backup of all the files on the phone on my laptop. I heard on here someone say something about (Helium) is that something I can use to do the back-up? If not how do I do the nandroid? Oh and I have titanium back up pro on the phone. I have some of my apps on the SD card with (GL to SD). How do I back up those apps? Or do I need to? I went to XDA to see about downloading ND8 and the link was bad! I'm open to suggestions on what my next move should be. I'm the kind of person that likes good step by step instructions on these kind of things so I don't brick my phone.

Nandroid is a backup made in custom recovery (twrp or philz). If you're rooted I assume you have recovery?
You can update just by flashing the nd8 .tar in odin. It will update and unroot you. You will need to re root by flashing a custom recovery in odin.